The PlayStation 3 and Vita version of Street Fighter X Tekken will have Cole from inFAMOUS and uh... Sony's cat mascots. So why doesn't Microsoft get any exclusive characters? Well, that's because Microsoft turned down the offer. Producer Yoshinori Ono had this to say:
But which characters did they want to be in the game?
I can only assume he meant it was too difficult to get Microsoft to play along. Phoenix Wright was "too difficult" to put into MvC3, but look how that turned out.
Putting a Halo character into a fighting game couldn't be that difficult. In fact, it's been done before. Spartan-458 was in DOA4 as a hidden character. And Marcus Fenix has been outside of the Gears of War universe before as well since he was an unlockable character in Lost Planet 2.
Which exclusive Microsoft characters do you guys think should have been in Street Fighter X Tekken?