Antimateria: Seems like too much of a hassle. And pinnacle isn't free in a long run.. Somebody has seen a lot of trouble making that but that doesn't sound very intuitive controls. =) I'm left handed so I don't never use wasd and I usually hate if the game seems to have too much buttons. Anyway it's a long game you get used to it whatever controls you use. I just don't think that controller is quick enough or accurate for this game. But what I believe is not always right.
Maybe religious leaders and such will understand that someday. ^^
Npl: Just what kinda quick and accurate do you need? I played a bit of Witcher (not my favourite genre, but 5€ is too hard to pass by) and the main view (all 3 of them) would benefit greatly from gamepad controls. Menus would need to be reworked, but apart from that what do you need a mouse for... you rarely need to point somewhere accurately, everything would work as good or better with a analog stick and tons of comfortable buttons.
Thats of course if we talk native support which is not likely to happen =(
It would be nice if there was a native controller support. But indeed those inventorys and menus would need to be changed. And some modder could propably do that.
There's so many times that you are attacked same time in opposite directions. So you need to turn the camera fast and then click the specific enemy in a hurry. That's where I think where mouse comes in handy. If you are good with controllers, that shouldn't be the problem either. Well, there's the pause button but then it would remind me too much of a dragon age:origins. In that game I didn't mind pausing and looking around and issue commands. Infact i preferred that method in that game.
Over the shoulder camera is somewhat third person actionish. And I use that, all the time. So a bit polish and it wouldn't be impossible to play with a controller.
And those other views, well now that I think of it, it could be fun just run around with a stick and not clicking the mouse.
There was a game which I thought could play better with a controller but it didn't support it. I believe that game was Divinity 2: Dragon knight saga. And If it remains without controller support I think that's a shame. Because it seemed a fine game.
All in all, it's a matter of taste. And nowadays games should support controllers (not just driving games) because a lot of people owns those. Well, perhaps not RTS-games, but I don't play those. =)
And yeah, with witcher 2 released and all these years. I don't think that cd projekt is going to make any patches which could add controller.