I like the semi-open world. For the most part, I think it worked really quite well. There's a fair amount to do that is interesting, and you can do as much or as little of the things that aren't directly related to the main plot as you like. There's some interesting stuff to be found there. Stumbling into things that are above your head and having to return later is great (would be better if loot weren't level-gated, but still). It also adds more replayability to the game, especially if your characters each don't do everything available, and do different things.
The only problem, I think, is that it hurts the pacing of the main plot if you do decide to do a lot of exploring. I'm sure that this could be solved in future games in a number of ways; I would certainly rather see that happen, than not see a semi-open world again.
But we learned that people like fetch quests that are covered up in imaginative ways. Perhaps it helped that the DAO UI didn't flash a "Collect Acorn 0/1 bar"? To point out they are on a fetch quest?
I'm sure that did help. I really wish there were a way to completely turn off such things in DA:I; it would make most quests more enjoyable to me. I also wish there were a way to drop quests from the journal that my character never has any intention of completing.
I'd also say that the Rhyming Tree's quest wasn't exactly a fetch quest, or at least, not the worst kind of fetch quest. There was a goal of one item, through which one had to go through a test or series of tests one way or another. There was some choice, as in, killing the old hermit or answering his questions. It wasn't a matter of going around and searching for X number of acorns hidden randomly in the world. It wasn't a particularly deep or inspiring quest, but I had no problem with it.
If each fetch quest had at least that much dialogue and decision attached to it in DA:I, I doubt people would be complaining (well, okay, some people probably would anyhow). I don't mind a few largely pointless fetch quests, as they can surely be avoided if I don't feel like doing them, but more in-depth quests are preferable.