Idea: Limit Break System

[Nephera]

2-hour abilities, while cool, have a problem: They are too powerful,
almost game-breaking. So either you tune Boss fights to be so hard
as to compensate for everyone using his 2-hour-ability (frustration
guaranteed) or tune them too easy so that you can zerg the bosses
by using everyone's 2-hour-ability. Both are not satisfactory solutions.

I feel like pandemonium warden was a result of the cross between this and a developer's MASSIVE ego, either way it was not fun for anybody but the hardcore-est of players