The health door itself isn't necessarily the problem, Its that it replaces the default 10mg door. I think a good balance to allow for the new doors/modes to stay in is to always have the default "10mg" and "1000mg" doors available, with a 3rd door that is rotating between the special modes, perhaps. maybe have 2 extra doors rotating between the 10mg variants and the 1000mg variants? that way you still keep the original balance of the game but allow focused builds to still have a chance to thrive in something like the "eyes" door, but that door wont always be available since it will still rotate between the other 1000mg door variants. Having extra doors might make the game a little easier, but it would also still be more fun when it comes to making new runs, like an "eye-focused" build, and you could always introduce difficulties if the game gets too easy.