thats the thing the game already has a bunch of ways to challenge yourself. if the settings aren't enough for you try rockin only SO's. This isnt DCUO (city of sidekicks). This isnt city of clones (Marvel heroes online) This is the Original, the best, never imitated always innovative the greatest to ever live CITY OF HEROES!
Personally i challenge myself with 4x8 on a blaster. Is is easy? No. Is it possible? if im careful, quick and clever, yes it is.