It is a find monster of a class sir. My only real critique is: Where's the capstone? Some, but not all associations offer capstones. I believe that all classes need a good capstone, and the ultimate jack-of-all-trades certainly does! I think there are three different ways you could go about it:
- Ensuring that each association has a capstone.
- Tying a capstone to the 20th level of Trissociate, so all Trissociates get it.
- Making three capstones, one each for the Battle, Skill, and Mental Foci.
Personally, I think you should do the first option regardless, and then add the 2nd or 3rd on top of that.
Also, where's the Truenaming!? (If you do add it, I'd use Kellus' excellent fix for Truenaming)