I don't know.
I still don't see the point of launching a new XBOX so close to WiiU. Nintendo hasn't really set the hardcore gamers on fire with WiiU reveal and its launch is probably due for Christmas 2012 instead of summer as previously thought.
A sleeker, even more living room friendly XBOX that emphises compatiblity with Windows apps should be enough to fend the competition for a year or two, there still are games like Halo 4, Bioshock, GTAV and many DLCs for the big games already out to keep momentum.
EDIT : other end of 2012 games are Assassin's Creed 3, Call Of Duty by Treyarch, Medal of Honor, probably a Platinum Games title, Dead Space 3.
How can you launch a next-gen console when previous gen is getting all the developpers' love? Backward compatibility is a given if only to accomodate the catalogue of downloadable games but if I buy a new XBOX next Christmas and its got a few (rushed) next-gen titles that make me wish Halo 4 should have been postponed I can't believe I will be happy.