Yes you are. Thank you.

The AI in civilization IV was so good because the devs learned what strategies most good players used in previous games and tried to implement them. In the end the game was much more difficult and challenging. And the strategy/tactics in Civ is a whole LOT higher then DA.
Yes, but the difference is the amount of processing power required in real time. My argument is the AI will be easily tricked no matter what with the current engine, tactics or no, and if we're going for more realism then processor requirements will go up steeply. The more realistic we try to make combat (since taunt is unrealistic) the more power required to run the game.
Compared to Dragon Age, where the AI uses very little tactics. Iinstead the game is made more challenging by throwing large numbers of monsters at the player. Which is the easiest way to increase difficulty. Taunt/disengage is a poor gameplay mechanic because it is something that no player would be affected by. It is a player only ability. And for everyone complaining about there mages being overrun - well what stops you from overruning the enemy mages? Nothing, but the player gets some super ability that prevents any monster from not attacking the highest defense character. It is just a poor design decision.
This is the thing: what is smart for the player to do is not automatically smart for the AI to do. The best move a player can make is have everyone kill an enemy mage first, and then cycle through the enemies, killing them one at a time. Conversely, if the AI did the same thing, it would be dangerous to a low-level PC, but less and less so as time goes on until that's exactly what you would want the AI to do. Even at low levels, the only difference between using taunt and determining targeting via tactics is that with taunt the player chooses who the target will be. Players can dynamically react to any situation, so if I see everyone attacking my mage, I'll do something about it. As far as I can tell, the AI doesn't have any way to react to that kind of situation.
You used the example of Civ IV before. Another difference between the Civ series and DA:O is that Civ IV is the fourth game (plus expansions and spinoffs) in a series spanning some 12 years with essentially the same game engine, whereas DA:O is the first game with this engine. Although it is similar to game like NWN and BG, it has different abilities, stats, and gear. I don't think they expected a lot of things players have done...
Before release, we were told that players would need to invest in almost every stat if they wanted to be effective. I remember seeing Chris Priestly's rogue with some 26 str, 36 dex and 34 or so willpower and assuming that was a good way to build a character. I just don't think there's any way they could have anticipated the way we would play. I mean, look at the description for Nightmare... things should get better in future games. Remember Civ II, with zero corruption for democracy/communism, letting you build 100+ city empires easily? They squashed that in Civ III.