Ignoring the existence of anti-heal.
What if the max HP for tanks was reduced to an average of 400hp but all tanks regen 50 health per second constantly, regardless of taking damage or not.
I personally think smaller healthpool tanks are a lot more healthy for the game than kaiju tanks. However, I also understand the necessity of the larger healthpools.
The smaller healthpools but active regen would allow tanks to play in a very high-risk, high reward manner. They would become even more brawl orientated. Chip damage would now be completely irrelevant to them (which is good as tanks absorb a ton of chip damage), however they would have to be more reactive to when they are getting focused down and understand when to use there defensive abilities.
Played correctly and the tanks would actually have more resources to make play. A large healthpool is great but if you don’t have the healing to support it, you are just a big damage pinyata. Active regen would allow for bigger, more risky plays but equally rewarding.