I can see people leaving Starfleet, turning their back against the crew or even turning bad, but I can't see any of them dying.
There were TOS episodes featuring the "deaths" of Scotty ("The Changeling"), Chekov ("Spectre of the Gun"), McCoy ("Shore Leave") and Kirk ("Amok Time"), and all got miracle resurrections. Casual, and even avid, viewers wouldn't necessarily have predicted the resurrections, except maybe Kirk's, since he was the credited lead actor. (De Kelley didn't get an opening credit till Season Two). Spock died in ST II and was left dead for a whole movie. The next film could certainly end with a death/funeral that gets reversed - or not - in a subsequent film.