There's actually no definition of "Best Healer" in the game. All healer heroes have their own strength and uses.
You need to know what healer is good in certain types of enemies and allies. As a Support, you need to help your allies effectively, and you need to learn how to counter enemies decently.
If you have burst enemies, go with Estes, although not so good if burst enemies can kill an ally quickly, but prevent them to burst immediately and sustain your ally to have longer time to counter. Estes is also good with high damage marksman so you can also deal some damage.
If most of your allies are melee, go for Floryn. Since her global healing damages nearby enemies and has a skill that heals allies near enemies that are damaged. To have allies that go near to enemies are her best teammates. Not because she is a global healer, she's best. Use her carefully because her ultimate is not a burst heal, allies can still be easily killed by enemies. You need to be with them to help them sustain more.
If most of your allies are poor in mobility or some are turret divers/Assassin-Fighter types, go with Rafaela because of movement speed bonus. She can give movement speed bonus to catch up enemies or help an ally escape quickly in battle or in the turret's range while sustaining them. She's also good in group slow and stun. But use her heal wisely. The movement speed bonus might be useful to change positioning quickly but it may also hasten allies on charging to death.
If you want to play 4 protect 1 strat, go for Angela. Angela is good for DPS/Core heroes. Since she is a single target support, 4 protect 1 (research this if you don't know, this is a common strategy on every MOBA games) is Angela's forte, she doesn't need to pick who she will give her ultimate.
If you want a combo of tank and sustain, go for Minotaur. If most enemies are mostly melee and your team lacks tank, Minotaur is a good tank healer. He can sustain a bit while tanking damage and also control enemies. He's a complete package for those who are Tank/Support mains aside Lolita and Carmilla.
KNOW YOUR HEALER SUPPORTS WELL. That's why you complain that the heroes are unbalanced and weak, it's because you pick heroes that's not suitable in the lineup. For example, picking Hanabi as marksman when most of your team are early game heroes.
ALSO PART 2
Pick your Roam Upgrade carefully. This is also an important part on what roam upgrade will you choose.
Just choose wisely, lads.
If you have thoughts and want to open a discussion, just give a feedback below.
