Tierlist healer patch 3.3, based on my main healer experience.
Furia is a god for me, she can just 1v1 easily everyone with she's dash and she's weapon and can have a very good adaption for the different situations. My most healed is with her (280K+), Thanks to his ability (healing laser), she can just make invincible 2 tank on point.
Jenos have good escape and can heal behind a wall.
Io can easily escape and 1v1 a flank with she's wolf.
Corvus have a very good adaptation in all situations.
Seris is very good, she's healing is very ok and she's ultimate is very powerfull when you know played her.
Ying is difficult to play when you dont have a good aim, but when you buy motivation and chronos, in low elo, it's very powerfull even if you dont have a good aim. In high elo, not the same, but anyway..
Mal'damba is good, but like ying, if you dont have a good aim, it's hard, because he's ultimate is not for healing you allies, but stay a good ultimate.
pip is good, but not enough, good esacpe with his rebounds, playable in normal game but for me unplayable in ranked game if you didnt main it.
Grover is good because he heals all time like 20 heal per sec, good ultimate but rest, for me, unplayable in ranked game because he need to have some distance to put good damage.
Grohk is not good at all, for me. He's more playable with a second healer, but stay very hard to play, just because i didnt have a very good escape and are more damage than healer, but very funny to play on damage mode.