^ Indeed. But IIRC, when he was first cast, the idea was that this would be more of a two-hander, as the studio were a bit wary of Tom's box office appeal (remember when Summer Redstone and Paramount broke up with Cruise and Redstone reckoned that Tom's couch-jumping behaviour had made M:I3 the least successful movie, even though it was the best?).
However, from what I can see, Tom has made a bit of a box-office renaissance, so my best guess (and that's all it is) is that they'll be happy to trust him with the MI reins all by himself again. But I know I'd be happy for the Ghost Protocol team to return.