I have to say that I think this game is astounding. But I have two issues:
(i) pace - I did a certain interest's quests before even heading to Skellig once, thinking they were super urgent, then realised I locked myself out of doing a number of quests because she simply disappeared then reappeared. I don't like that you can neuter yourself so easily and lock out content by doing this kind of thing. Also, someone I did not kill at the end of Witcher 2 did not reappear in this game, though I've seen play throughs on YouTube showing a quest involving X.
(ii) Interest continuity - I romanced someone in Novigrad, yet at a reunion scene at Kaer later, the other person (who I flat out rejected - it was a very bitter quest actually) kissed my character in front of my romanced person. I had just rejected her, flat out, and where did that kiss come from? Something doesn't seem to match with the choices made, and there's also the fact that somehow the game seems to default you into one interest despite the fact that the previous two games were focused on the other. (Despite the fact as well that the current default interest recovered a lot faster than you did, and made no effort to approach and help Geralt recover).
But having said all this, it's a fantastically immersive game. Combat seems to get much easier over time - I'm doing the cat build + quen (only the first tier) and on bigger monsters if I manage to get whirl off next to them it's almost an instagib on Death march. But I don't play these games to have incredibly difficult battles (Jenny of the Woods wrecked me a few times then I outlevelled/geared that encounter) but for the story, which I find quite simply outstanding.