I recall a battle in the gardens of the Grand Ball in Orlais, and Cole remained in the back with my Mage; sometimes behind after using Leaping Shot. And my Mageompanions have moved away from opponents with Fade Step enabled; how Dorian killed a boss in JoH.
I want to see them move intentionally to keep an appropriate distance without using abilities. As far as I can tell they use abilities in a reasonably sensible way but their positioning is determined by where they end up after using an ability and they don't otherwise adjust it (except to gain LOS). This may sound picky, but its really my biggest criticism of the AI - ranged characters don't intentionally withdraw from melee combat unless withdrawal is a result of using an ability.
Incidentally, I'm not claiming that DAI AI is significantly worse than other Bioware games. I can certainly recall ME companions doing some pretty stupid things, and DAO and DA2 essentially gave you the ability to write your own AI for companions so I have no idea what the default behaviour was like.
I also think that there are some interesting challenges in the way that abilities work in DAI. For example rogue archers get bonuses for flanking, and have Long Shot and Leaping Shot. All of these require careful positioning to be used optimally, and Long Shot and Leaping Shot are better at different ranges.
Mind you, since tactics are really not that important in beating the game at its highest difficulty this probably doesn't matter very much ...