I think people are looking at this the wrong way. DA2 is not an RPG in the same sense DA:O was. DA:O, you're writing your destiny for a story that hasn't been told yet. DA2 is the retelling of the rise of Hawke to become the Champion of Kirkwall from Hawke's perspective. Their storyline has been laid out to show events as he saw them. You complain there was very little depth gone into with the first Act, and then there was no real choice involved in the final act. But that is how a retelling would indeed go. You aren't really making decisions, you are simply discovering how the decisions made influence others, and what the character did along the way, as the story progresses to reach a specific end. I agree, it is not the best way to do an RPG game, but it is true to what they set out to achieve, and there is undoubtedly a reason they did it that way
Act 1: he's grinding for cash in the hopes of investing in an expedition that he hopes will restore his family's lost fortunes. All the quests are essentially aimed at that - gaining loot - and introducing the characters that will make up the party and major plot-lines later on. No real depth to it, just as it would have been from Hawk's point of view. They were random encounters whilst he was working to another goal. The idol was a random find that would prove to be important later, but for now it simply demonstrates that it is capable of making people act irrationally and against their nature.
Act 2: Idol found, family fortunes restored. Now begins the Qunari and the Mage/Templar story-lines. Qunari are naffed off because they're stuck in Kirkwall whilst they hunt for something, and Kirkwall doesn't live up to their expectations. Mages are being overly oppressed by the Knight Commander who has taken her normal oppressive outlook and is pushing it to the extreme due to the influence of the idol. Mages start to turn to Blood Magic for the power to escape the oppression (note: vast majority of blood mages in Kirkwall start to appear after idol found, not before. Maybe things are getting worse? Guess why). Goes into a little more depth this time around, as the character is more involved in the events as an established local, rather than being an outsider who is just trying to scrape up enough cash for something. He is starting to get involved in the realities of being a major player in his new home.
Act 3: He came, he saw, he conquered. He's the big cheese now, and with that comes the responsibility. In the major political conflict going on atm, both sides turn to him in the hope of attaining his influence as a result. However, that idol is still there influencing Merideth, and that continues to pressure the mages to act irresponsibly. The mage Anders, influenced by the perverted spirit Vengence, sees the injustice of Meredith's actions and decides that enough is enough. Decides to remove compromise as an option in order to prevent the situation from possibly occurring again. This works, as Meredith is officially a loon by now thanks to the idol. She overreacts and instead of punishing the guilty party (an apostate, not even part of the circle. I mean, come on, that's gotta be an overreaction) decides to punish the innocents, acting far beyond the bounds of her position. Orsino eventually respond to this in desperation, and resorts to blood magic himself, using the research of the mage who killed Hawke's mother (who was, pretty obviously, a master of the craft). Blah de blah, battle, Orsino flips out (hey, we all have our breaking points, not like he didn't have good cause), then the cause for Meredith's insanity is finally revealed. Battle again, game over.
The point is, each act has clearly defined perspective. It goes into as much detail as would be likely to be experienced from Hawke's point of view at the time, and no more. Life isn't one huge quest, it's a lot of little ones, and each one has a story attached to it, but eventually, we only have one present, and that is what the game was intended to bring you to. It was not a single quest like DA:O was. There was never any single enemy that had to be defeated at all costs. It was the retelling of a life over the course of 8 years, and some of the things that affected it. DA2 was an attempt at something a little different, and you are all judging it based on the normal RPG format. Perhaps it's time to step back and look at it from a different angle, and try and see it for what it really is?