Platinum or Dragon Dogma would be my two likely guesses.
As for anyone suggesting Fallout4/ME.. that would cost MS a couple hundred million easy (300m)... don't see it myself. Especially now PS4 is selling so well. This is one of those deals where if you are a struggling company you don't care what platform it comes on, that would make Plat or Capcom the two likely candidates.
Edit: Rainbow Six would also apply if as someone else mentioned has had troubled dev... easier for MS to come and scoop it up when a game has struggled to do well.








