The only thing that I could possibly point out on the Combo System is that it could blow the passive rings out of the water. Since rings can be upgraded, the passives would have to have stronger/multiple abilities. Okay, the passives saved themselves so I can't think of any other possible bug in the Combo System. I shall return to my thinking. confused
Well quite honestly, I would imagine the passive rings could give you a 'greater' bonus to Aura than the active rings, on top of whatever passive skills they would lend the wearer, and the passive abilities could even be increased by the aura system to improve specialization with more than just 'active' rings