But don't you think there might be something you're born with that makes you more likely to choose to be heroic?
Regardless of what I think (and I don't care to get into a nature-vs.-nurture debate), I'm fairly certain it's not what Gene Roddenberry thought, which is the point.
But... did you read the next paragraph of my post where I decided that wasn't really what I was trying to say?
Heck, I'll even let that point go and agree that the choice of the word "innate" may have been a little off the mark. How about "inherent?" That being a quality essential to the person's character, but not having been present from birth. I'd say that's more to the point of what I was trying to say.
(I guess I should've just deleted that first part, but I like a little stream-of-consciousness. I guess it just clouded the issue this time.)
His ideal wasn't "I'm not capable of killing," but "I will not kill today." It's right there in the words spoken by his heroes: heroism comes from the choices we make.
But even disregarding the nature-vs-nurture debate, don't you think some people are more prone (for whatever reason) to make good/heroic choices, and some people are prone to make bad ones? Innate, inherent, or whatever, the people that ultimately turn out to be heroes are the ones who more often make the heroic choices, because there's
something in there that makes them respond that way. The thing that differentiates Kirk from Khan or Gary is that his natural tendency is to make the heroic choice. And it just seemed, from my personal purely subjective viewpoint, that nuKirk didn't display that natural tendency. He was making choices that coincidentally were heroic because he loved a challenge, or had a desire to be top dog, or a combination of any number of things. But my personal opinion is that doing good (or what he believed was good, since that's another pretty subjective judgment) wasn't one of those reasons.
And we can argue about what his motivations are all day, and I really don't think there's any way for either side to win the argument. But I can tell you that that was my perception at the time, and I didn't find it appealing.
Who knows? Maybe my perception will be different next time I see it.
If we got to see Kirk, who as a recent Cadet is practically the same person he is to become, where is the character's growth? I rather not see a Kirk who can accomplish everything as a young man in the same way he does as an experienced starship commander.

But he did. He saved the Earth from an opponent with vastly superior technology, surmounted a challenge of overwhelming odds, came out of a harrowing, seemingly impossible mission unscathed. How is that any different from what the experienced starship commander could do?
The only thing that was different to me was his attitude while he did it.