It depends who do them.
Bioware? Get trashed to kingdom come
CDPR? They are a nothing short of miraculous .
Exactly so saying that there will be no fetch quest is plainly false because "hunt" quest are confirmed and what scheme do you think they will follow?
There are fetch quests, and there are fetch quests.
If you make the process interesting enough, through investigation, witcher senses, etc. even a humble fetch quest can feel more interesting.
And to hunt an illusive and actually dangerous monster, sounds more interesting to me than fetch 10 elfroots and 10 pieces of lamb meat.
Besides, fetch quests or not, graphical downgrade or not, TW3 looks like it's going to be the best Fantasy / RPG game of the last few years.
And if it will allow modding, it will probably remain so for a while.