Wayyy different games. I don't think they can be compared except as separate instalments in a game world, you'll obviously end up with a favourite but it'll be the one that most closely is designed to what you like in games. Personally i like all three, and it's really hard to give one the edge for this reason. I'll give my reasoning below.
DA:O is to me a very nice traditional rpg - of course, I well remember it still got bashed in comparison to bg2 by quite a few - with the typical allotments of quests, PC-style controls with more options given more keyboard keys, etc. I liked all that, but i thought the story was incredibly generic, like... easily the most generic in the DA series. However, it didn't really matter since there were several quite awesome sidequests along the main quest arc, and it was nice to explore this new world, meet all the characters and its lore strewn about. The origins were also quite fun.
DA2 is to me a rather neat attempt at making a game that is told from a novelist's perspective of sorts, and I feel that it mostly succeeds with a rather nice companion dynamic, great dialogue at times, and to me the best protagonist of the three, despite the limited choice you've got. The story is told with a neat day/night cycle (I really liked this feature, wish it was used even better) with a deliberate choice, and it is tighter and zoomed in way more than either DAO or later DA:I. It's a relief to not play the same type of "savior of the world" once more, although that too is personal bias. Of course the game wasn't without its flaws like the other two, and the repeated use of some maps with barriers simply moved around made things a little silly. Combat was different, but to me it doesn't have to mean console bias just because a game plays as a third person action game, as long as you keep depth. It was so so, but I didn't hate it.
DA:I is to me the game that tries to correct somewhat limited space by giving us huge zones to explore, at the expense of a more clearly definied story within each one. There is definitely a lot to learn about what you do, but if you ignore codex entries and skip through tertiary dialogue here and there you're basically going to find it rather empty in that way, inbetween the story missions. It has rather enjoyable third person action combat, but at the expense of the tactical view which is still rather limited. Also, I feel like a lot of the frankly rather neat AI settings for individual abilities was a missed aspect to tailor the fights you didn't control quite as much, from the previous games. However, if you take the game for what it is it is a beautiful part of Thedas to wander, and I feel like in this game, the support cast of your companions are more interesting than the Inquisitor. Sometimes this works, sometimes not... for me, eh. The Inquisition (the faction) is not my thing, but I still enjoyed the journey a lot, from the companion dynamic to exploring it all, and finally... to be able to jump. Yes, that's really highly subjective, there. 
Retour en haut
If they were really hardcore they would have left Bioware already (my friend always tells me this)
