Who knows, it could work out great. I remember at GDC a few years back, before the Tomb Raider license was given to Crystal Dynamics, Warren mouthing off (politely) at a panel on licensed IP that he'd drool over a chance to work on a license, like maybe Tomb Raider. He claimed there is so much opportunity to work within any licensed IP's ruleset, and to turn out something of quality.
This is his chance to prove that point, I'm very hopeful that he wasn't just blowing massive steam.