The visuals are great & I know the feeling, when you get a new graphics card you want to go on a magical mystery tour of graphics.
But actually what I like best about Witcher 2 is that instead of being long & grindy, it's short & dense, with many branches, so it's different when you play again.
Someone like me, who doesn't have loads of time to play, can have a great time, finish the game, have a lot of choices to their route.
If I really like it (I did), then I can play again, maybe 6 months later & have a substantially different adventure.
I know this route takes almost as much man-hours as building a longer game with less branches but I think its a more satisfying type of game for a a range of different players.
And it neatly sidesteps some of the compromises involved in trying to be accessable to less hardcore players, while still giving plenty for the harcore players to dig into.