levi also has a mechanic that punishes healers who over heal.
That's... not anywhere close to being the same thing.

The mechanic is based on a per-cast basis. If your heals were stronger, you'd have to cast fewer heals. In other words, you're not being punished for overgearing like the DPS can be; it's exactly the opposite.

It can also be nearly entirely circumvented by healer swaps, which is probably how you're intended to handle it anyway.