Captain Kirk was never a stack of books with legs. was he smart? yes. was he highly educaded? of course. but he was an daring, adventurous ladies man first and foremost. maybe even too adventurous for Starfleet standards. through all of TOS. we only know about his academy years - being a 'stack of books' - from hearsay and nothing in 09 contradicts that.
Kirk confirmed in "Shore Leave" that as a cadet he was "positively grim." I'd call that more than hearsay.
Also, "first and foremost" is a poor choice of words for Kirk's "ladies' man" characterization. At
first, in the early first season, Kirk was portrayed as anything but a womanizer. He was initially written as an extremely serious, dutiful military officer with no time for the distractions of the flesh. In "The Corbomite Maneuver," he complained about being assigned a female yeoman because he had no time for the distraction. In "Mudd's Women," he was the only human male in the crew who was essentially unaffected by the women's allure. In "Miri," Rand is upset because he
doesn't look at her legs. The only times he shows romantic interest in Rand or any other member of his crew is when he's in an altered mental state ("The Enemy Within," "The Naked Time," "Dagger of the Mind"). In "Dagger," he was deeply embarrassed and uncomfortable about having danced and flirted with Helen Noel at the Christmas party, and a deleted line would've explained that he'd only done so in the first place because he'd thought she was a civilian passenger.
Although we saw hints of his off-duty romantic life in episodes like "Shore Leave," "Court Martial," and "The Menagerie," the "womanizer" portrayal didn't really emerge in full until the second season. And though that was presumably due in part to Shatner's own personality affecting the writing of the character, it was mainly because pretty much
all male action leads in '60s and '70s TV were expected to be womanizers and have frequent romantic entanglements with one-time guest stars. Ironically, the trait that we tend to consider a defining attribute of Jim Kirk was actually one that made Kirk a
less distinct personality than he'd been to start with and turned him more into a generic TV hero.
So the new Kirk is actually distinct in personality from the original. He's closer to the popular caricature of who Kirk is than who Kirk Prime actually was. But that's justified in the movie, because the timeline changed and his father died right after he was born. Abrams Kirk was raised without a father and thus became much more of a renegade than his more studious counterpart. We're also meeting him at a considerably earlier point in his life, so he's less seasoned. So the new Kirk isn't
supposed to be like the original. But his arc in the movies is about his growth
into the Kirk we know -- his process of growing beyond that immature renegade and developing into the great leader he has the potential to become.
It's like
Arrow. The Oliver Queen of that series isn't like the Green Arrow of the comics, but that's because the whole series has been a long-form origin story showing how he
became the Green Arrow. The Abrams movies are the same way. They're an extended origin story whose end point is a version of Kirk, Spock, and the others who are essentially the people we knew from TOS. So of course they're different from the characters we know, because they haven't become those characters yet.
