Chris Pine has only got the chance to play Kirk as a hothead and a troublemaker. We haven't seen him grow into the Kirk we're used to seeing. That's for the next couple of films. I don't really see anything that would prevent nuKirk from being just as noble as KirkPrime was.
As for nuPike? Since he's avoided the accident that permanently crippled him in the original timeline, I'd say he has potential to be even greater than the original Pike ever was. Pike could be the Starfleet C-in-C by ST XII.