You really can't take too much away from any trailer. It's aimed at the masses and is highlighting the action. The team involved keeps saying that they are adhering to canon (official Trek) wherever it is present and working around holes where it is not.
Agewise, most of the actors are in the range they are supposed to be, with the exception of John Cho, who is way too old. Anton Yelchin, I believe is only 17 or 19. Although we see Kirk riding his bike to the construction site of the Enterprise, I'm inclined to believe the main action of the film will happen several years later, with Kirk in his late 20s, only a few years from getting his own ship and the much younger Chekov having only recently begun his training. I'm thinking Pike has already retired from active command and is already training cadets (he did want a career change, remember?), with Spock as a student instructor, a postion Kirk also held at one point. It would explain the absence of Doctor Boyce, Number One, etc ,etc.
The situation is depicted as an emergency with cadets and officers alike being assigned to various ships, so the posting is not permanent. Kirk wasn't even supposed to be onboard. He will meet these people but will not get all of them under his command immediately - you wouldn't fill the bridge with all green officers would ya?
This works for me.
