True.
But resistances (not immuneties) seems like a better solution. It adds characteristics to enemies, making fighting them feel more diverse. Not everything should be about our characters and their gear. Enemies need their differences too.
Constant dmg sounds kinda boring in its own way. Ebb and flow, and deciding when to do what, can make combat more interesting. You do not need cooldown for that. But they, as well as generator skills etc. can add different flavors to builds. They just shouldn’t be required.