Skyrim isn't the only game with such world and it isn't the base model of open-world ideas. There are a lot of RPG with that style you never know. You should not have to base your opinion on Skyrim.
Except the developers specifically stated that they wanted to draw from Skyrim's open world, and it's clear that they tried. The only real problem I have with the semi-open world (because it's not a true sandbox; it just has really big areas) is that, for most of the areas, there's no story reason to go. You don't have to go to those regions. You can completely ignore Emprise du Leon, which really, should be a major plot point but isn't, and still continue on.
I don't think the side quests are really the problem because Origins had sidequests in every region and so did DA2. Most of DA2's first act was just a bunch of side quests. The only thing that I think creates the issue is that, because most of the areas are optional, there's a complete and utter breakdown in the pacing of the game. There really isn't any pacing. I've said this in another thread, but it's super weird to be level 16 and hear Cullen tell you that Inquisition forces are ready to march on the Arbor Wilds and you still haven't finished half of what's in your journal. And you don't need to finish half of what's in your journal. You may need to level up or get more power, but basically the Inquisition is waiting on you to deliver a potion for some guy's wife, instead of, you now, defeating your enemy. The story ends up being all over the place and the sense of urgency inherent in previous Bioware games is noticeably lacking.