I actually enjoy DA:O and think it's a quite good game. It's in the same situation as the first KOTOR game in my opinion, the plot is rather generic and doesn't try to do anything new at all but it's still executed in a satisfactory manner. I don't consider generic to mean
bad. Most of the characters are enjoyable (with a couple of exceptions), the game is long, polished, and the Origins system plus the absence of the dialogue wheel gives you more freedom to roleplay your PC. It also has much less of the "cinematic" crap that plagues Bioware's recent games. Of course DA:O has many flaws, but I still like it overall.
Mass Effect 1's plot is on the same level, it is generic sci-fi space opera with lovecraftian horrors from outer space, but it's not
bad. Bioware always did better whenever they tackled a simple, generic plot, because they (used to) execute them well. The problem is when their delusions of grandeur caused them to aim for more creative personal plots or plain deeper plots, which Bioware writers simply cannot grasp. Anyways while the plot of the first ME wasn't bad, it is the game that marked the rise of that accursed dialogue wheel and Bioware's infatuation with the "cinematic" corruption, a sign of the decline to come. Also, the combat system was atrocious, not only did they make the game popamole, but they failed at making the shooting decent.
Mass Effect 2 did the characters much better than the first one and the plot is more personal, sadly for Bioware the plot itself happens to suck, starting with the nonsensical death and resurrection of Shepard (senseless christian imagery 2deep4u) and culminating in the retarded giant Terminator that the Collectors were building. The shooting, in turn, was better done this time around, because it seems that in Mass Effect its quality is inversely proportional to the quality of the plot. Good characters and some rare good moments (like the Suicide Mission pre-retarded Terminator) salvage several parts of the game, and the plot, while awful, has yet to reach the hilarious depths of fail where ME3's plot resides. Also, "progressive and mature" Bioware shoves Miranda's ass on the screen ever second, which is hilarious.
Mass Effect 3 finishes improving the shooting, the force of inertia causes the game to have a couple of good character moments, all of this while the rest of the game descends to storytelling hell in a spiral of shit, of course.
It made the game something more than just a b-space opera popcorn with some great parts... It showed that Hudson and his team got pretty ambitious, which of course could mean anything for future projects...
The ending is actually the worst part of the entire series, but it's not the isolated mistake some people believe it is - it's actually a symptom of what happens when you take Bioware's delusions of grandeur, obsession for the cinematic and a desire to leave "safe" plots behind and try to make something with more depth and creativity. It represents the failure of the writers and a massive decline from the generic, safe, but ultimately well executed plots. It is both pretentious and hilariously shallow, comes out of nowhere -with the exception of some rushed, extremely amateur failures at foreshadowing- and both the idea and execution were incredibly retarded. This is because the intent of the ending wasn't providing a satisfactory conclusion, it was a desire to aim for the artsy without knowing w
hat the artsy even is.
This is what happens when Bioware writers have their ego stroked so much that they believe they can make a story with the potential to be more than -good for what it is-