I would've preferred he was just left as John Harrison, one of Khans top people and by far the most intelligent & manipulative. The ideal choice for Marcus to thaw out and use. He was the one pulling the strings and Khan was just the figurehead. Or something..
A glimpse of Montalban frozen as well thrown in at the end!
Only problem is he would not be dead. Do we want them to pull a Terminator: Salvation in a future film?
Better to say they failed to revive Khan and he died. Didn't the unit initially malfunction. Maybe because Scotty was not there, Khan died.