Free Agent - NA
This is just my opinion. Please do not attack me for any "misguided judgements."
Edit: Added Maeve (whoops) and touched up on some explanations to make them flow better or to expand on things I may have overlooked.
ss
Makoa: Hook = free kill if your team focuses the target. A powerful ability at most levels of play if you play with your team since the ability serves the target up on a silver platter. Especially powerful with coordination since the chance that a focused target doesn't die is essentially zero. Ult is a powerful zoning/stalling ability. Surf decks are good at enabling aggro play and he can also play shield builds occasionally making him quite flexible.
Torvald: Field Study and bubble CDR make him quite an insane support. Empowered DPS or aggro tanks are very difficult to stop early game and his cripple is pretty powerful as well. Although Wrecker can help alleviate some of his pressure the bubble will still tank hits for the target, allowing the bubble to retain value even with Wrecker 3. Torv could also just bubble a backline DPS that isn't being focused and let the damage amp do the rest. Otherwise you'll just get ROFL stomped before you get enough Wrecker to start with. Coordination required.
s+
Khan: High damage hitscan, decent sustain/team support, and lots of immunity abilities (shout and no CD shield) which allows him to avoid most abilities that would be dangerous to other tanks. All this comes together to make Khan a hard to kill damage machine. His ult is also a free pick for his team while his grip has a stun that can't be Resilienced which can cancel channeled shields. Although his shield's size makes him quite subpar at main tanking everything else is above and beyond.
Atlas: Effective at all ranges, good damage output like Khan, and crazy utility. The lob can reel in retreating enemies, cancel healing, or send enemies back to base just to name a few uses. Rewind is a powerful immune ability, increasing Atlas's effective HP greatly while also allowing for riskier plays (Note: It is not affected by cripples either). The shield, with cards can grant Atlas speed, good sustain heals, and can't be destroyed. It can even absorb certain ults. His ult is good for stalling and isolating targets given your team has some coordination or the game sense to capitalize. Even though his cooldowns are big and he has not real movement skill with a proper deck and CD rotations he is still incredibly hard to kill and provides lots of damage and utility to boot.
Cassie: Good mathematical DPS at all ranges with left click and decent damage per shot means she doesn't lack confirmable damage either. Possessing consistent high burst with abilities, decent mobility, and heavy amounts of peel/survivability with a proper loadout Cassie is a damage champion who has everything and can support a wide variety of playstyles to adapt to the game flow. Big Game makes her especially good with tanks being so strong and the talent itself being so strong against them while she barely loses out on anything else from the other talents. The ult's reveal is quite a good team support ability while the CC immunity and speed granted to Cassie herself promotes more aggressive play.
Jenos: Damage amp is very strong, especially on damage champions. His Stellar Wind and range cards make him quite safe to play. Decent HPS, but very strong overall team sustain with the recent buff. He can mark 3 targets at once with Chronos 2-3 and a proper deck so half his team has damage amp. His heal through walls combined with the uptime of his heals make his healing incredibly consistent. His ult is hard to hit, but can be effective when used at the right time (Ex: Ulting on top of your tank to ward off a Drogoz ult).
s
Barik: Good damage, good survivability with Bowling Ball deck, good sustain, decent mobility, and deployable shields. Barik is pretty good at everything and his sustain gives him great synergy with Jenos who is the dominant support. He is borderline S+ when everything is taken into account, but he doesn't quite make it because although he fits with anything he isn't a crazy outlier in any category. He will do well, but you can't expect a Barik to make the game changing play.
Bomb King: High sustained damage, high burst, great area denial, a good ult, both hard and soft CC, and a blaster. Generally an aggressive DPS BK outputs lots of pressure, but his projectiles limit his range so he can struggle into snipers or powerful mid long DPS like Cassie. In spite of this weakness it usually represents a lesser problem to his flexibility as the ability to detonate bombs midair greatly diminishes the weaknesses associated with most slow medium speed projectiles. Close quarter maps are very good for BK in particular.
Damba: CC, healing output, speed buffs for tanks, and can heal from very far. An all around good support. His heals in particular carry a nice balance between raw HPS, consistency, and burst meaning the heals will almost always be effective in any situation. His ult is especially useful for dealing with dives or to turn the tide of a team fight.
Ash: AoE cannon has decent range and proximity detonations (blows up when near an enemy) making it very good at bullying, especially towards squishies since she can poke from a decent distance around obstructions. The AoE nature also makes it good for spreading Caut. Battering Ram makes her a strong aggro tank, making her long dash a safe and consistent gap closer/escape. Her ult is strong for dives and holds with the added stun giving it additional utility as a setup. She has potential main tank presence with Fortress Breaker, but there are usually better alternatives. Fortress Breaker should only really be considered in the case of a shield heavy defensive comp, most notably into the weaker Wreckers like Lian.
Inara: Super tanky with Mother's Grace and a decent CC ult. Especially good on smaller maps like Jaguar Falls and Brightmarsh where her wall can literally cut off entire routes. Pairs well with higher HPS healers due to the % heals. Low movement speed, especially while shooting, and below average damage makes her a primarily a point bot.
Evie: High mobility makes her one of the few flanks capable of consistent dives at higher levels. Decent damage and although she doesn't have the best burst chaining abilities like Soar can allow her to finish targets relatively quickly without taking much damage. Wormhole makes her quite safe and very slippery. The ult is good to secure picks of any kind, especially on the backline.
s-
Furia: Cherish has seen some use in the PPL which makes her heals more consistent and when paired with her fast charging ult makes her good for aggro play especially. She does good damage and her beam gives her good self peel and support.
Sha Lin: Although he lacks DPS in his M1 and other backliners have more consistent burst or better utility Sha is still a good bursty back line DPS that is effective at all ranges. His tank melt is good thanks to Planted and the bursty nature of his damage makes him more suited to deal with slippery champions like Evie than other characters.
Maeve: A flanker that is capable of poking is already a major advantage over the competition and with proper cooldown management Maeve can also be quite slippery at the same time. Although her mobility doesn't allow for hard dives like Evie and there are quite a few DPS with better burst making it difficult to directly engage the backline Maeve is still very safe overall.
Imani: Slow on M1 and a powerful root to zone/confirm picks. Splitting Ice gives her nice multi target damage that other mid long range backlines don't have and her double cast is not hard to build either which gives her some burst potential. More vulnerable to dives even with her root due to her unwieldy movement and her recast mechanics preventing her burst from being on demand.
Pip: A mid long range blaster with good damage and burst with Catalyst. His slow is quite strong and Moxie gives him crazy self sustain making him a good brawler as well. His ult even with Resil has a 2 second minimum duration, is AoE, and can be used from a safe position, giving his team a free pick(s). He struggles with hitscans due to his big head and doesn't have a safe mobility option limiting his aggro capability a bit.
Ruckus: Essentially a beefy DPS Rocket Barrage gives him the consistent burst needed to finish kills. Two dashes gives him good mobility and combined with his shield makes him hard to kill when played right. He is still quite squishy for a tank and can be easily focused thanks to his low movement speed while firing. Additionally, his DPS lacks burst despite being good on paper and suffers from damage falloff, which can make it hard to deal damage without rockets. His ult is powerful, but makes Ruckus a big target at the same time. Ruckus is a tank that can make plays, but carries his own fair share of risks so tread with caution.
Lian: She was already beginning to fall off in the PPL before nerfs and after nerfs she finds herself here. Her burst is no longer hyper consistent, but the damage in the associated combo has not been nerfed which still gives Lian some of the best burst in the game. Even with nerfs her burst is consistent enough and with Eminence she is still quite powerful at most ranges. Mediocre burst and mathematical DPS on her left click in her Presence downtime makes her vulnerable to tank pressure, but her damage is still consistently high across the board. Being hitscan gives her more use against champions like Drogoz or high speed flankers and at longer ranges.
Tyra: Hunting Party marks are really good at locking down problematic targets for long periods of time at very little cost. They can be applied from very far away, last a while, and makes the target very vulnerable thanks to the massive teamwide damage amp. Tyra herself also gets incredible melt from her M1 thanks to the mark boost which with cards can have a very low CD making the ability very consistent too. The firebomb is decent area denial, giving her insane tank melt as well. Her ult is a good damage boost that only does good for her already insane damage output. Despite everything she is still somewhat vulnerable to direct tank/dive pressure since she has no movement skills, but good usage of her marks (better with coordination) can keep the enemy pinned, alleviating this problem somewhat.
a+
Kinessa: Pick on open maps or ones with long sight lines like Timber Mill or Frog Isle. She does more sustained damage than Strix and headshots have better one tap potential. Her ult is pretty good too and is probably her major edge against Strix, giving Kinessa real play making potential. Hampered by weakness to tank/dive pressure. Sight lines can also be avoided with enough game knowledge.
Strix: Better burst from quickscopes and his pistol make him better at dueling/anti-flank. Stealth also gives him the upper hand in long range fights. He still suffers the same weaknesses as Kin, but to different degrees. Dive pressure is less thanks to stealth and his burst/flare, but without a movement skill his sight lines are more easily avoided.
Drogoz: Lots of counters, most notably mid long range hitscans, but can be quite strong on maps like Brightmarsh with lots of roofs. He can safely deal quite high blast damage when played into the right comp using WYRM and his other abilities are still quite good AoE damage abilities without the other talents. Combustible has a more niche use on close maps like Jaguar Falls or into stacky comps like triple tank where Drogoz's superior AoE over other blasters would be more useful. His ult is easy to punish, being very telegraphed and putting Drogoz in a vulnerable position, but when used at the right time it can be a very consistent tank execute.
Fernando: Doesn't excel at really anything, but still has decent damage output, a strong shield, and a strong ult. Formidable allows him to be somewhat of a main tank with some staying power which might be needed when going for a more sustain/defensive comp. Would probably drop to A if not for the lack of real main tanks available.
a
Seris: Her healing output is on the higher end for sure, especially her HPS which can save people quite easily early game, but that's about it. Her ult has good setup potential, especially with coordination, but during that downtime she really has nothing besides healing to contribute. Her orbs are hard to hit and don't deal much damage and she can only do one task at a time.
Vivian: A worse Viktor, but could be useful due to her very consistent stream of damage and her shield which makes it harder to dive her.
Androxus: His weapon does not do well outside of close range and usually loses too much damage to fall off to effectively burst enemies. However his mobility is still pretty good and his burst is pretty high when he is close so when he cycles his dash and rev CDs well he can be quite slippery. His burst is not crazy however and his low range on his revolver makes dives quite risky even with his mobility so he suffers against the more meta backline DPS. Many things can go through his rev and any hard CC cancels his dashes making flanking even harder. He can work, but it is hard to pull off and usually you are probably better off playing someone like Evie who does more for less effort.
Viktor: Generally outclassed by the other backline damages in most aspects. A decent hitscan who gets the job done. Good DPS, but low burst which makes him bad at 1v1s with the more relevant DPS. Grenades are unique, but not enough of a niche to get him picked. You'll usually pick him when there's nothing better, but sometimes you might want a Viktor as another backline DPS in a triple DPS comp or if you would like a more constant stream of damage than the more mainstay backline DPS.
a-
Grover: After numerous nerfs Grover doesn't provide anything that other supports can do better. His heals are neutered and his cripple has been cut drastically. His limited heal range just makes him even worse. It doesn't help that most of his heal is concentrated in a small window which, once Cauterized, means he loses most of his effectiveness, and unlike other healers his cooldown is far too long to compensate. His ult is still pretty good though with its high HPS which acts as a team reset and will work even under Caut 3 as long as the team buys Rejuv.
Ying: Acceptable amount of heals, but brings nothing else making her subpar overall. Most of her burst heals are on an upfront heal that can be Cauterized with a cooldown that is a bit too long to make up for the shortcoming. Her illusions also have limited heal range and deployment range which hampers the consistency of her heals. Her escape and damage are alright, but other supports simply do much more. If you ever plan on using her it is best to play a more passive poke orientated comp to make use of her illusions bodyblocking and to maximize their heals.
Terminus: Siphon is good and with Decimation he can do quite some damage, but decent players not feeding the Siphon makes this difficult to pull off. At that point he is left with a melee weapon and a 15 second movement skill that doesn't go that far anyways. Ult is pretty good though.
b
Skye: Good tank melt, but little mobility makes her easy to punish when the team is decent. This forces her to play at a bit of a distance and just makes her a worse Tyra for the most part. Niche anti-tank pick.
Moji: High damage up close makes her similar to Skye in that she's only good for tank melt. Better mobility and Magic Barrier cleanse make her more survivable than Skye, but she suffers from abysmal damage outside of her spray range while still being easily punished because her survivability is still pretty shit in general. Might be useful on close quarter maps, particularly against tanks.
Grohk: Niche damage dealer. Good against deployables or against more stacky comps, but easily pressured with his only mobility/immunity being a 1-1.5 second Ghost Walk with a proper deck and lacks any burst. His Shock Pulse with Maelstrom merely does chip damage that gets easily healed so his DPS role has limited use. Ult gives insane utility however.
Dredge: There are better blast damages who aren't as easily dived/pressured out as he is due to having on demand escapes with more control over their usage. Good DPS with all talents, but much harder to confirm than other blasters. His only niche is his above average zoning due to bouncing projectiles which makes him a consideration on maps like Jaguar Falls with tight quarters.
Willo: Low damage overall and vulnerable in ult. Her area denial is nice, making her above average in this department, but it is still not really enough to make her generally useful. Maybe useful against stacky comps with low aggro pressure.
Talus: Due to low mobility Talus might struggle to flank and be forced to tank melt, but unlike other tank melters Talus is a squishy with strong falloff which makes him less consistent at dishing out numbers because he can easily be pressured out. This also applies when he tries to pressure the backline. He is dependent on his Overcharge to get anything done as well, but he is the safest of the niche picks thanks to his Rune. Potentially useful on close quarter maps with low burst.
Zhin: Whirl builds allow him to kind of go in and out, but it is still quite risky due to Zhin's low immunity and the windows of punish in between each whirl reset. Can poke with Yomi and has decent damage. His burst becomes kind of good if he animation cancels his M1s with his Whirl. Only consider on close quarter maps and when there are little burst champions.
c
Lex: High movement speed and DPS, but low range and no instantaneous movement makes it easy to pressure out the Lex before he gets close enough or to turn on him when gets in. Against a decent team Lex is easy to lock down and made useless.
Koga: Agility gives barely any speed to close gaps and his short dashes don't do anything either. His SMG has no burst and low total damage per clip so racking up damage is difficult. His dashes take a long time to end so it's easy to shoot Koga as he exits and his lack of burst usually forces him to shoot for a bit after each dash to rack up any damage, making the window of punish quite large. His ult rarely gets any kills and the lockout after the end usually just means a dead Koga if he tries to go for kills so it is mostly a glorified immunity frame at best.