The new systems proposed has me thinking about the classic +8% Damage Reduction mechanic. We have pure melee heroes who always get +8% DR, hybrid heroes who get it as a proc, and ranged heroes who never get it. What if instead of making that distinction in the hero design and defensive trait, what if we added a non-stacking +8% Damage Reduction passively to all melee filler (basics, single-target spenders, etc) powers whenever they are slotted?
Think of it this way: if you've got a melee filler slotted, you're commiting to spend time in melee. You are now essentially a melee build, even if none of your other powers are melee. You could choose to slot both a melee and ranged filler, but that versatility comes at the sacrifice of a precious bar slot. In that case, you've made your sacrifice. How about we start thinking with bars and do away with that hybrid proc mechanic?
Edit: Hehe, nevermind! Some good cases were made below why this wouldn't work. You win this round, logic!