I actually quite liked DA2. But the things that were not good about it really did not to be that way. The reused environments and dull wave-based combat were just lazy. The third act felt rushed, or at least improperly foreshadowed. The end of act 2, in terms of Hawke's story as biopic, should be the midpoint of the story (To be unspoilery about it, Hawke's on top of the proverbial world, and things that were brewing are about to go seriously wrong). The initial release had more bugs than Isabella's downstairs (I kid, I kid!). All of this just felt sloppy, like getting the game out quickly was more important than getting it done right (See also, KOTOR II, which so obviously could have been really, really good).
Also, the simplification was good in a few ways (For one, there were much fewer balance issues in terms of combat, unlike in Origins, where you could do stupid, stupid, things as a mage so long as you had a meatshield), but it mostly was a whopping case of "if it ain't broke, don't fix it." The cries of dumbing-down have a bit of classic-RPG nostalgia coloring them, but damned if I DA2's character creation really does lose a good amount of substance for no reason other than simplicity for its own sake.
So yeah, it wasn't that bad. It's OK. It's just that it arrives at that OKness with no actual OK parts, just the good stuff we expect from Bioware alternating with pointless and bad missteps. As a game, it's the equivalent of my 11th grade Pre-calc class. Back when I took it, I got a B-minus overall. But my exams were either A's or D's, with no in-between. That's (I think), why DA2 attracts so much distaste: because there's a very good game in there, but it has a number of glaring, infuriating, un-ignorable flaws.