I think al Qaeda doesn't really know who its new leader is. After all, who decides? And what if some of the other contenders and their followers disagree with the choice? The REAL riot would be if WE are the ones appointing this guy the new head, and the confused rank-and-file buys it simply because it's the clearest of the many conflicting messages they're receiving on the subject. Our military and CIA are pretty good at psy-ops -- I wouldn't put this past them. He's already well-known, so he's a plausible choice. What if we chose him because he's the only serious contender that we know we can locate and take out quickly?
Oddly, DebkaFile doesn't seemed to have weighed in on this announcement yet.