My hunch is that it was about consistency which they simply couldn't afford with their budget/time constraints. Think about it, if the entire game was like that with choices and consequences abou waging war and making the ramifications seem real it would require more work than what seemingly went into the game we got. I think at some point they just realized they couldn't make the entire game like in this demo and they went with a cheaper idea of time-sinks and such. They mentiond that these types of story-things in the exploration areas just didn't work very well, so there's already a big clue right from the horse's mouth.
I don't think the change in direction we saw to what we got was something those from Bioware were completely happy with either. I think they're proud of DA:I but they probably realize its flaws and I also read a DGaider blog about cutting content on his Tumblr last year where he wrote something along the lines of "at some point so much is cut that you feel like you're making a shitty game".
I don't worry about future Bioware products for being intentionally video-gamey and time-sinky. I just fear the same problems that plagued DA:I's development will strike NME and hinder its development too. I don't think it will happen twice because DA:I developers have learned and they can share their experience with working with frostbite and incorporate stuff like the DA:I dialogue wheel easily with the NME team.