Problem is you completely eliminate any thrills from seeing Kirk and Spock in danger because you know they go on to work on the Enterprise for another thirty years.
A coworker of mine who wasn't really into Trek said he was amazed by how his wife would get so pulled into a Trek episode because of its teaser, knowing full well that the main crew would never die (save Tasha, of course). Sometimes people go into things knowing the outcome and they just don't care except for how it's told, hence adaptations of books or other various prequels. I'm not sure if anyone really expects Kirk and Spock to die for good, reboot or not. It'd be interesting if they did, but I just don't see it unless that's the end.