You do know that The Witcher 2 is linear and not open world as Skyrim? It's also a PC exclusive game. Seriously, it's like comparing BF3 to Skyrim.. If the Witcher had the amount of detail that Skyrim will have, your computer would explode.
No it wouldn't; witcher 2 uses streaming tech to load such huge maps it doesn't split into cells like ES games do. SOOOOOOOO skyrim can easily look like witcher 2 (of course it could only look that good on the PC). IT could also look as good as CRYSIS 1 quite easily without affecting performance to much; seeing that i can load a map on crysis x20 the size and has x100 more things going on than any cell in any ES game.
The reason Bethesda is holding back on the graphical department is not because of lack of funds; they simply do not want the PC version looking that much better than the console version.
Could you imagine what would happen if Skyrim had the graphical fidelity of crysis 1/the witcher 2 on the pc version,BUT on the console version looks like the current incarnate of the game (of what we have seen of 360 shots). Console consumers would be quite angry, though there logic for there anger would be flawed. Makes me wonder how BF3 is going to play out.