Is it known how many powers Sylar had already stolen before the confrontation with Peter?
And I'm having a hard time believing there isn't some catch to Peter's power; as it is, he's better than Sylar or even a Rogue from X-Men...At first I thought Peter's power would only work in close proximity - which would make sense as he'd be a great team leader, being able to double the powers of all his allies and even enemies during fights. Then I thought maybe he might only be able to recall 1 power at a time, and perhaps with limited function/potency and/or with great difficulty. Then I thought maybe it had to do with family - he can fly because of his brother and could heal because of his niece, although we now know he can go invisible, draw the future, manipulate time, and meddle with telekinesis - all at will and apparently without breaking a sweat.
As cool as it is for there to be an uber super hero, it makes it kind of pointless to have other heroes or even villains as no one is going to be able to challenge Peter in his current portrayed state.