Truth be told, when I play an RPG, I don't see myself as an active agent in how the story should unfold; I see it as a way it can unfold, namely if I was the one at the helm. This whole save transfer nonsense Bioware has gotten so obsessed with isn't doing it for me. In ME1, it allows me to make a decision on the structure of the single most powerful governing body in the galaxy. Naturally, one would expect this to have quite an effect on the plot in the sequel. It doesn't. What you see of Council space in ME2 is the same regardless of what you pick, the Citadel still has ridiculous (and completely worthless) security measures put into place, there's still some crooked politician running for office in Zakera Ward with extremely strong anti-human sentiments, and the Council, regardless of whether it's still alien or completely human, still won't give you the time of day. Really, the biggest consequence of that fateful and climatic decision you make at the end of ME is whether or not you get to see a Turian make quotation marks with his fingers.
Overall, in the wake of the save transfer between ME1 and ME2, the whole
So you seem to complain about ME in that regard and basically you would want the decisions in DA to have no aftereffect at all and there should simply be one canon story, disregarding what choices you made, in order to tell a stronger story?
Then why are you so obsessed about the impact of your choices with Morrigan? In that case my ending could be the canonical one, and yours is the "fake one".
But anyhows this creates a problem for people who didn't happen to finish the game in a canonical way, basically the game would say "you made the wrong choices" and that you played the story incorrectly. In such a case it's preferrable to not do direct sequels at all and rather tell unrelated stories like in TES and Fallout, where you can completely avoid that problem.
And yes neither Bioware nor any other company can make a game where the decisions of the prequel have massive wide spanning effects on the sequel. Trying to do something like that would massively divide the ressources for the project and a player would only get "half" a game. Choice in these games is mainly an illusion. You will always end up playing the same overarching story, no matter what choices you make.
But for me personally that's fine. I'm content with seeing even just small references to choices I've made in the past. Because even if they don't alter the main game much, the experiences you had are still acknowledged in the narrative.