Did you complete DAO? If so - which ending?
Very good answer Kein
The fact that DAO has several endings proves that it is not a linear game. I myself have seen 4 different endings only in Origins not to mention Awakening. Your actions do modify the pace and development of things.
For me DA is the best RPG game of 2009 and in terms of RPG features it can't be compared with DKS, which btw I loved for its action-oriented "RPG" style.
I won't even bother talking about ME because I really made an enormous effort to stay awoken when playing the game. That means I hated it.