The Hero System is probably the best system to cover all the craziness from different players/characters inclusive of genres of every type with a well designed point based character creation system, and additional character points available if weaknesses (called disadvantages in the Hero System) of equivalent value(s) are taken (BALANCE!). The experience/reward system uses those same character creation points as the reward, i.e., the most you play, the more you get rewarded and the "better" the character becomes. Awarded experience points can also be used to "buy off" disadvantages. Adding new powers or removing disadvantages should always be RPed. Points csn be saved up to be used later for larger "purchases." I can't imagine anyone here really being interested in the system though. It's also incredibly complex and I cant imagine most here using it without complaining about "the maths make my head hurt." More importantly though, and Wyo touched on this, it would necessitate balance, limitations and actual accountability. It'd never happen. But it's a nice thought.