Why do so many Item sets have to be % based?

Mashille

I find is strange how so many item sets, including so many new ones are % based. Would it not be possible to have sets that do something when someone does a specific thing like 'When you knock and enemy off balance' or 'When you damage an Enemy above 80% health' or other kinds of stuff along those lines because at the moment the huge number of 'x% chance when doing/ taking damage' is insane.

I'd find the new sets more interesting and engaging if they didn't roughly resemble half the other sets in the game.