DA:O suffers mainly from the design-by-committee approach of Bioware. There are glimpses of genius, after all there were plenty of talented people who worked on the game, but the conclusions of the committee were as follows:
1. Since MMOs are popular, make DA:O use familiar MMO tropes in UI and quest design. Do this again for the third game when we make it.
2. According to our residential nerds those George R. R. Martin books are all the rage, so let's copy those as our theme for the game. Then let Gaider just do whatever for the sequels. That will work out.
3. Marketing has determined that romances are remarkably positive for publicity and even people who will never play the game will help spread the word through their indignation of buttsex.
4. We must milk this franchise as much as we possible can, squeeze blood from this rock with DLCs galore. Sell them ingame. Do whatever it takes.
5. Use visuals and music to distract from the inevitably limited content and story we're putting into this, something awesome must happen when people push a button.
Despite this there are really cool things in DA:O and it is certainly better than the sum of its parts. There was plenty of potential and Gaider's fanfiction of Westros wasn't half bad. But potential has to be followed through, otherwise it fizzles out in a lame sequel. And boy did it, fucking DA2.
edit: this is obviously the truth and if you disagree.. nah it's just my opinion, my post-mortem of the game.