It isn't the quests in themeselves. I'm fine with most of them (again in themselves) and the shard/mosaic/astrarium/etc stuff doesn't bother me.
But the feeling that we could have had more quality content instead of this stuff, in many areas of the maps, ew.
Bloat.
I don't think DAI has only 20 hours of main content though. I'd bring that to 30-40. Which would have been fine for a shooterish Mass Effect game, but maybe could be considered disgraceful for Dragon Age.
I'm largely fine with all this side stuff in my main Nightmare playthrough. In fact, I feel every bit of exp/gold/loot because I want to make sure I'm optimized (as well as my RP allows at least) for the main storyline. I wasn't strong enough for the Mage quest (Lv 6-7) and I needed to grind some levels (Lv 8-9) in order to deal with it, and that meant completing most of Hinterlands, half of Storm Coast, and some of Forgotten Oasis. I think the game is good with this in mind, but for lower difficulties, it just gives me the feeling of, as said earlier, bloat.
I can understand this design, to a degree, for a studio trying the 'open world' concept for a first time, just as I gave Bioware a bit of a pass for doing the 'shooter' concept for the first time with the first Mass Effect, and the 'cinematic' concept with KOTOR or Mass Effect (depends what you first consider cinematic), and action-combat with DA2, but after that, I get annoyed.
If:
-DAI DLC is more of the same of this (Hey here's a zone! Oh but 1/2 or more of it is utter filler with little interesting. Go get shards! Hahaha!)
-DA4 is more of the same, or worse, contains even MORE filler and pushes even MORE into being a MMO without declaring itself as such
-'ME4' seems to not have taken a clue from DAI, and instead has this problem as well
Then that's a bad sign, to me. But core DAI itself? Okay, I'll go through your hoops. Because Bioware marketing is right - its a 'wonderful world'. I like doing random crap in it. But I won't like doing it more than 1-2 times, and I'll be looking for substance elsewhere.