When he was going to blow up the Enterprise just for the hell of it after getting his sleepers back?Khan was nothing but an out of control One dimensional screaming madman? When did that happen?
... Anyhow, San Francisco Chronicle critic Mick Lasalle once wrote some interesting thoughts on revenge as drama:
There are two things wrong with revenge as a motivator. The first is that there's no urgency about revenge. Revenge can be dished out now or later. It makes no difference if the worst has already happened. The second is that it usually places an action hero in a state of mourning. A revenge plot is a sure way to sap the energy out of any protagonist.