The ONLY thing we have Re: 'young Kirk' from TOS is "a stack of books with legs" (from Where No Man Has Gone Before; and his run ins with Finnigan and an affair with an older worman from Shore Leave.
Now, NOTHING in the new Star Trek film contradicts any of that. Hell, young Kirk in the bar states he'll graduate in 3 years instead of the usual four and DOES IT (and no I'm not talking about the promotoion in the film as before that Kirk IS a senior set to graduate after only three years). You can't do that without major work or study, thus he probably was STILL "a stack of books with legs." Finnigan and the older woman affair probably still happened as well, so please show me where the TOS info on 'young Kirk' was contradicted in the film?
This Kirk is hardly "positively grim." He's cocky, jokey and arrogant--he has more in common with Finnegan and Gary Mitchell than he does with the Kirk as he is described in TOS.
The "out in three years" thing? Already addressed this: the movie folds that into the entitled pretty boy brat thing. We hear it but we never see Kirk working his ass off to get there. Instead, we
see a guy who uses "study" as a euphemism for fucking so often that his best friend swats it away with a "my ass" when he hears it.
And hey, this is totally keeping in with the zeitgeist, where bright kids think they should get As for being bright rather than for working. I'm a teacher, I've seen it again and again.
But you know what? You can argue that the two interpretations are not mutually exclusive, that the humorless cadet TOS
implicitly established over its first season is consistent with the cocksure punk we see in XI. Because it was implicit, there's no way to explicitly refute it. But it's still revisionism. If you're cool with that, so am I.