Agreed. The Game is also pretty close to flawless.
A game engine is not as simple to compare.
It couldn't render a truly open world like that. They get away by cutting certain corners. See vsions post in the Witcher 2 thread for more information.
Yes, as far as I understand, the RED engine could not be used for a massive open world like Skyrim.
So far, I'm barely past the prologue in the game, enjoying it immensely, but it is a very different sort of experience from TES games. The RED Engine seems designed more for a branching interactive movie kind of plot, which could work for lots of Action RPGs, but I don't think this can work for the "go where you want, do what you want" sandbox experience intended for Skyrim.
So far the only gripes I have with TW2 are pretty minor. The mouse works just fine in-game, but if I pause or open a menu, the cursor becomes difficult to maneuver and moves across the screen slower than molasses. Also, some areas seem to have needed another color timing pass, as they look seriously oversaturated. Really enjoying it though.
As far as "ubersampling" goes, I'm just hoping Bethesda releases an official 2048x2048 texture pack. If they add features like ubersampling that can only be used with dual or triple desktop video cards, sure, why not, as the land of Skyrim will surely be enjoyed even more by those with high end hardware. Unfortunately, I probably will not have a system with SLI to take advantage of any features like that.