Bring back Persuade and Intimidate checks. I didn't hate the radial menu from ME being imported into DA in and of itself, but I (and I imagine more than a few players) was savvy enough to figure out that when there were choices to be made, anything on the left side was some quick and easy way to get what I wanted. Getting what I want by being a smooth talker rather than a killer is how I like to play Dragon Age, but I want to build a talent for it first. That makes the moments when I successfully persuade a character to do something they normally wouldn't all the more special.
Also, more party member conversations outside of special scenes and story choices. This crap had its inception during Awakening, which could be forgivable since it was an expansion and the story took place in a limited span of time, but in Dragon Age II many, many years would pass and it was ridiculous how limited I was in managing the moods of my party members. This was especially frustrating when I learned at the ends of Act 2 and 3 that I had to have a strong friendship or rivalry to get certain party members to go along with me. My story actions would antagonize an ally, and instinctively I would try to win favor in conversation (and if you were antagonistic you would piss them off no matter what you said or did, which was even more BS).
Thus I was in a middle ground as affections went with two characters, and apparently them hating me would make them inclined to fight beside me when I picked a side they didn't like as opposed to having a complicated relationship and still being enough a good guy by doing their personal quests and having their back in trying times. In Dragon Age: Origins, I played it like a conventional hero, which pissed off Morrigan, but we hit it off pretty well in conversations and special gifts she fell madly in love with the Warden in spite of her not liking my goody goody ways.
Which brings up one thing I would like to see in Dragon Age III, enough time has passed for Connor, Feynriel, the dwarven casteless son and Morrigan's kid to have grown up. I want to see what kinds of people they become due to the player's choices. Getting to see a clear contrast between Morrigan's natural child and demon baby would make creating two different save files all the more worth it.
Oh, based on what I read in the wikis, it's possible to create a scenario in which both Loghain and Alister survive the Blight. I'd love to see what possibilities are created by these two characters' survival, and how different combinations of choices like the bargain with Morrigan, the Architect, etc. either let you find a third way to solve Thedas' problems or screw you over.
Hell, I want to know how the hell the final arbitrary choice in Dragon Age II made any difference.