That's a bit different. The Joker is a staple to the Batman universe, you expect Batman to fight the Joker at some point. Khan, much as I am a fan, isn't as important to Star Trek.
Khan is important to TOS in a way, because he was the only recurring villain and was also carried over to the movie series- for a movie that was a successful revitalization of sorts for the franchise as well.
I think people, especially those who have only very limited knowledge of oldTrek, might be interested to see "Kirk's old enemy" back.
He's got super-strength so you can have huge fighting scenes, he has charisma, he's intelligent, he's got a cause, he is human, and a link to a time closer to ours. I'd say bring him back.