User blog comment:Krankenheimer/Critical Strikes/@comment-16737371-20140416201947

Crittical chance is fair in LOL because they are not all that RNG. If you replaced Crittical chance with % bonus AD then all AD champions incuding casters like Riven or Zed will do far too much dmg(like they already don't) and even if you set it to only effect Auto attacks then you still have champions like EZ or GP who would get crazy consistant crazy op poking power. Imagin how much it sucks when GP crits now when he pokes you it will always do that dmg.

Your just creating a scaling problem that would require the whole game be shifted to make it work.