P.S. I agree that Witcher 2's third act feels weird,
Angthoron. It feels incomplete, like there was supposed to more exposition (about Foltest's kids who are suddenly kidnapped, etc), dialogue and reactivity there. I've always assumed it was unfinished. The EE tried to address this but it didn't quite do the job.
Yet to play the EE, apparently there's now a nice combat mod to go with it, so once I replay W3, I might take it for a spin.
The problems the way I saw them were basically the
very many sidequests, some of which had nice pay-off, and some didn't have any at all, which basically led to a situation of "Eh why did I do this, and why should I do the next one", for me at least. It had too much real filler. There's also what you mention, but the real killer for me is Act 2 end filler and Act 3 start filler. I want to do it because I want to see the pay-off, and at the same time I loathe doing it because it's so much busywork and some of it will be pay-off-less, like that goddamned "Kill a million harpies" quest. There's also too many loose subplots going on that are kinda hard to keep track of. What's my main objective? Find/save Triss? Find the killer of Foltest? Thwart the conspiracy? Oh and suddenly there's all this new cast of characters in A3 to meet, too, again, more diffusion.
Say what you will about the "Find Ciri" goal of W3, at least it's concise. Just find Ciri. Yeah, you'll do a fuckton of other stuff on the way, but your goal is clear anyway. W1 goal was pretty clear too, in the end of the day - stop the crazies. W2, no clear goal for the endgame, not really.