I didn't like the movie Kirk. He was indeed an asshole and I can't see that Kirk becoming our Kirk.
But since it's reboot Trek, it doesn't matter. The characters can differ all they want. I can enjoy the story knowing that they're not the same characters as in the regular Trek world, but alternate Trek world characters.
And this is the essence of it: it's a reboot. nuKirk is a reinterpretation and not an extrapolation of TOS Kirk.
Again the film is rewriting everything so it boggles the mind that some folks insist that it's in addition to what came before rather than a rewrite of what came before.