I have a couple problems with the OP. First I will say, Once again very well written.
However, It falls flat for me. For one it prefaces the argument by stating this is "for old bioware fans" and then falls to reference Baldur's Gate or NWN. Secondly it comes off as a giant spermgasm for Mass Effect, a series that I never played except ME1. My personal experience with that is it was extremely buggy / crash heavy and the story didn't intrigue me enough to keep trying to get my system to play it. So I returned it. Not only that my memory of ME1 coincides with the release of the also buggy NWN2 which was released by Obsidian.
Now this is speculation. But... I always suspected Bioware dropped the ball because they were so concerned about the Mass Effect game, they didn't fight for the right to party with Wizards of the Coast to keep the DnD license. DAO was released after 3 or 4 years of talking about this new amazing RPG they were developing. ME2 was released at about the sametime as DAO.
The Result.. DAO was a let down for many of us "ACTUAL" old bioware fans because it wasn't the Classic RPG we were expecting. Luckily they did release a toolset, and that made the game a little better for some of us. Many, many many of us and you can reference the old black and blue forum, felt that too many resources at BW were used for ME2 and thus the DAO was made with a basic MMO type cooldown mechanic that everyone else was using at the time. No creativity or complexity in the game ruleset at all. The only thing new it added was the ability to control AI, which a lot of people on this board are mistaking for tactical game play.
It irks me when people say DAO is cRPG, when it was anything but. AI control does not = tactical game play. Its nice and was a big miss in DAI. The thing is regardless of the weak ruleset DAO presented, they did present a new and interesting world with a great story line that keeps me coming back.
The thing I like about DAI is that I can actually ROLE PLAY my character, I've played the game from 3 different personalities and the result is different war table missions, different attitudes from the world NPC's and especially companions. Compared to DAO, there were some nice character interaction but nothing on the level in DAI.
To me it feels like a real living world that changes based on my personality. My favorite was going thru the game as a complete *******. To me that's the story of this game, the way the way world around you is formed and building this community.
The biggest miss is changing the magic schools, wtf? How do you change the magic schools?
Lastly, I will agree with your point about the main antagonist, I was never concerned about him, nor was he concerned about me. Until it was time to go kill the clown. Major Plot Fail there. My hope is that he was supposed to be integrated in the keep siege mechanic that was left out, and that will be the DLC that ties this thing together. We'll see.