Dana is on record saying that it wont happen in the forseeable future as the talent pool is just not deep enough. I happen to agree, there are plenty of women in Japan as evidence by JEWEL, SHOOTO, DEEP, Smackgirl and other promotions but they all either wilt or are held sporadically. The pool is rather shallow in the US when it comes to female mma (it's much better with regards to either straight grappling or striking). Carano was a bit of an anamoly, without her and/or more like her I don't think women's mma will ever rise to the level needed to be accepted in the UFC.
The merger between the UFC and WEC has been a long time coming and I see only good coming from it. Smaller fighters that are extremely talented and put on incredible fights will finally get mainstream exposure. I foresee Aldo, Torres and Faber being synonymous with GSP, Valazquez and Silva.