Well, Mission: Impossible 4 just got a lot more interesting with the news that the movie will be directed by The Iron Giant and The Incredibles creator Brad Bird.
The rumor was confirmed by Tom Cruise himself in a recent interview with Empire:
[W]e’re working with Brad right now. I don’t know if I’m allowed to talk about it but everything’s signed... Brad is doing it... The Iron Giant, The Incredibles, Ratatouille – Brad is enormously talented and JJ [Abrams, who's co-writing and producing the movie] and I are having a blast, cranking away... We’re having a lot of fun. I like working with people I just love hanging out with. You get to hang out and laugh and talk stories and movies and technology: what are we going to do?
Bird won't be the first Pixar director to make the switch to live-action; Finding Nemo's Andrew Stanton is already working on a movie version of John Carter of Mars. Bird himself was already prepping a live-action movie based on the 1906 San Francisco earthquake, before this announcement; it's unknown whether that will be pushed back as a result of M:I4.