No-one has been able to clarify why the fuck everyone thinks Khan was so bloody brilliant. He was a bad captain who made all the wrong decisions, had no idea when to shut up and was too self-absorbed and plain stupid to keep his intentions a secret until nobody could stop him anymore.
His crew were moronic evil minions and he was an overlord with a grudge. His motivation was pretty far-fetched: it wasn't Kirk's decision to maroon him, much less his job to babysit the man once he got dumped on Ceti Alpha whatsitsnumber. It was his own fault, because he was too incompetent to get the job done in the first place. Fat lot of good his supposedly superior intellect did him. He didn't actually come across as being smart at all. Sure, the Feds abandoned him, but his being beaten was his own fault and he must have known that.
And don't get me started on the monologues.
I can relate to Nero, I sure as hell can't relate to Khan, like, at all.