I would not characterize myself as explicitly "burned-out" or tired of the fantasy MMO. That said, I belatedly noticed an interesting fact in what I've been up to of late. Since DC Universe Online went Free to Play in November, I have capped characters in three non-fantasy settings - DCUO, Star Trek Online, and SWTOR.
In fairness, I've also spent some quality time in fantasy settings as well - I cleared the patch content of Cataclysm, I picked up half of the levels I was missing in LOTRO, and I finally capped out my Rift character. I'm also not planning to jump on The Secret World, which is the newest non-fantasy launch. That said, perhaps there is a trend here that I wasn't paying attention to?