I'm with KD -- Insufficient Data, Ask Again in Six Months.
Even then, I doubt you'll get a lot of consensus. Or there'll be vocal dissenters, at least.
If I were forced (by evil three legged cats armed with Discombobulator Guns, say) to try to judge or predict from what's been revealed so far, I'd say it sounds like a revision -- for everything except possibly the monsters. With all the changes to types, amounts of skills, number of feats, etc. (nevermind changes to individual monsters, like the "more everything" pit fiend), it seems like it could be a fairly hefty set of changes. No single change seems very big, but as a whole, the cumulative set might be large.
What really bugs me is the number of 3e monsters that aren't going to be in the revised MM or the revised SRD. ToH, MM2, BoVD, Monsters of Faerun, Green Ronin's fiend books, Monsternomicon, Eden & Atlas's bestiaries, etc., plus the odd beasts thrown in other books. That's a quite a lot of monsters for me to change (or try to ignore the nagging "Hey, the MM equivalent is so very different" thoughts; though with things like there not being a Shapeshifter or Beast type any more, it seems like there are some changes that would be very difficult to ignore); or it's a lot of product for me to buy again; or it's a lot of work for several publishers to do to make revisions available to their customers (publishers with less resources than WotC, which thus means less chance of free revisions).
But that's all pure guesswork. Thankfully, secret agents in the employ of the CIA stole the Discombobulator Gun from the buccaneer felines, so I'm safe.
