I like the new mage troops, they certainly spice up the magic tree. They also add a little more diversity to the possible troops you can build. Not to mention they just look cool.
However I think they need a fair bit of work. They have a few problems:
-There is no real reason to actually give them robes. You are better off equipping them with armor. The fact the AI doesn't is a huge weakness.
-Their damage is completely tied to their equipment, their stats never come into play.
-There are no interesting trait combos.
In order to fix these problems I would suggest allowing some stats like intelligence or spell mastery to boost the damage of the staffs, or add a min req to use the staffs. Then add some robes to the beginning of the magic tech tree. These robes could do everything from protect from fire, cold, pierce, or ranged attacks. They would also all boost intelligence or spell mastery so that mages have a reason to use them. Also there is no reason robes need to have 0 defense. Then you could add a intelligence boosting trait to unit design.