The Wormhole wrote:
Sorry, I just don't view Khan as being the forefront villain of Star Trek the way that the Joker is for Batman.
Well, he is.
"The Klingons" aren't a villain. They're just a bunch of stock bad guys who folks are confused about because of TNG (in fact, one of the writers of ST '09 gave the "reformation" of the Klingons as a reason for not using them in this one. That works). Khan translates into a very specific image for mainstream folks who are aware of Trek at all, and that's Ricardo Montalban facing off with William Shatner in that Trek movie with Kirstie Alley.
There is no Klingon character in the history of Trek that approaches this level of recognition, and announcing that in the next movie Kirk will fight Klingons buys the studio nothing in terms of cutting through media noise. It's like saying that next time out Batman will fight some bank robbers hiding out in an abandoned warehouse.