This isn't me saying that the leaked specs aren't real, this is me saying that we may not have full picture yet.
This is me saying that MS' behavior looks, sounds and smells like Nintendo behavior, IE, when you don't have anything to really brag about about a certain aspect of your product, you keep quiet instead. Nintendo talks up their tablet, social aspects, new nintendo online stuff, marketplace and so on. They STFU about the fact their console has a CPU from the late 1990s.
MS will talk up kinect and related stuff (voice tracking, facial recognition, whatever), undoubtedly xbox live improvements (whatever they may be), marketplace, things of that sort. If they aren't aiming to beat sony on raw hardware specs they're not going to talk much, if at all, about them, other than at a basic level, such as so-and-so many CPU cores and thiiiis much RAM, things of that sort. Big numbers look impressive, but if your numbers are smaller than the other guy's, why draw attention to the fact?
I don't think it's very likely there will be any sudden surprises on the 21st in the numbers department. As already mentioned, ASICs of this magnitude take a LONG time to develop, and games also take a long time to develop. MS pretty much literally cannot have kept things secret all this while or else they'd shoot themselves and all of their games developers in the foot. It just isn't realistic, and certainly not practical.
...Yeah, it COULD happen, almost anything could happen according to theories of quantum mechanics. Just really unlikely, though. No credible rumors or leaks have given indications that durango will differ substantially from what we have seen suggested so far, and a number of credible rumors/leaks have said that durango WON'T differ substantially from what we have seen suggested so far.
I'm sure durango will be great, consoles aren't all about big numbers. If nothing else, nintendo has proven that often enough over the years.