That is an excellent point. I think this came out of the limitations of the early days of game design. Not that Dragon Age could not have included more player choice, but consider something like Space Invaders. You were given a simple role - to shoot down invading aliens - with no in-game option to do anything else. This approach led to people, players and devs included, to assume the player did not really need to question what they were doing.
It took an additional effort and thought to create an environment where the player could choose a different approach. Imagine a game like Space Invaders where you could attempt to negotiate with the aliens :) It's a lot of extra code to allow for something like that. I just love that some developers were thinking that far ahead and making that extra effort...