What everyone else is saying. What really defines Star Trek? To me, it's how the characters deal with the challenges they face. It's not the size of the screen, the explosions or even the villains. It's what the characters do and how they act..
Star Trek is, in part, about the characters. One of my disappointments in the new Trek is that our heroes have been largely reduced to their pop-cultural images. McCoy's role is not simply to crack wise, but to raise important moral questions. That stated, it was nice to see Scotty conscientiously object to Kirk's mission. I think Pegg is growing into his role nicely.
I think the greatest improvement that could be made would be to ground the action in a stronger story. Instead of having a string of action sequences with a revenge-driven villain, it would be nice to see a Trek movie centered on ideas.
The movies have tended to be bigger and dumber than the television shows, in general, but I don't think that has to be the case. I think they can do everything that they are doing well in terms of action, pacing, quips, etc., but add a little more heft.