Katsuhiro Harada has been talking about Tekken X Street Fighter quite a bit on his Twitter feed. Recently he said that he would be holding a Tekken X Street Fighter roster vote on the Tekken facebook page sometime in the near future. This was in response to a fan who asked if Karin and Poison would be in the game.
In addition, Harada said that he is considering giving the SF side of the roster access to a special gauge or meter, something that hasn’t been done in the Tekken franchise yet. He says this special system is “simple but cool” but says nothing else about it.
Finally, Harada said that he is considering bringing the game to the PS Vita as well.
Source: Harada’s Twitter