I would have killed him, but done it differently.
Have him survive the attack on the conference, then he takes command of the Enterprise, only to sacrifice himself fixing the engine core. Then he stays dead so we don't need that stupid magic blood crap.
It also makes Kirk fight to get command of the Enterprise back because he doesn't just get it handed back to him. Seriously, what was up with that. They made such a bog deal about it in the beginning of the movie, only to throw it all away when it became inconvenient. And it also lets Kirk be the one in the big fight with Khan instead of Spock. What is the logic in having the hero of the piece be in a coma during the climactic fight?