I'm not sure I'd agree with Andy that doing an animated series today would be a risky or unusual move. It's actually common these days to have animated shows to cross-promote with movie franchises -- we've currently got them for Spider-Man, Iron Man, The Avengers, and Transformers, for example, and the Transformers Prime animated series is actually produced by Kurtzman & Orci, who have expressed interest in doing a new Trek animated series too -- and may even be actively developing one.
The difference between all of the named series is that they have their origins in comic books or toys, which--historically--lend themselves to their natrual "cousin" in animation with greater ease than movies. After more than three decades, ST is still more a live action property than not--created for TV, but spun off into film. While TAS was appreciated at the perfect storm time (post TOS) and at a time when once-exclusively live action TV properites were adapted as cartoons by the truckload by the major animation companies, I tend to agree with Andy about the risks of producing a new
animated series, when ST is first and foremost live action.
Comic characters turned into film, then turned into spin-off cartoons are not percieved the same way.
Further, the NuTrek films are still trying to justify their existence in a modern film world that has surpassed it in terms of interest, spectacle and basic appeal (post Potter, Rings
, Hunger Games
, numerous comic book adaptations, etc.), so a new cartoon based on NuTrek (or any Trek, for that matter) is a dicey concept at best. This was not the case when TAS was created, as the interest for more TOS was at a fevered pitch. That made the acceptance of an animated version easier than what ST as a franchise faces at present.