I am also inclinded to say Telekineses actually, without having any experience with it. I will try it this week though. What I'm thinking is that teleporting a scoring Tervigon around would be quite awesome and quite hard to counter. Since you spawn termagants before you move, I think that prevents you from teleporting and then spawning. But still, you could spawn next turn, it is still scoring, and it is still a big scary monster with template shooting attacks.
The other telekinesis powers are not too bad either. The dome is not too different from catalyst. 5+ invoulnerable can sometimes be better like for gaunts vs scatter lasers. Crush is not bad either for taking out tanks or trying to snipe characters and malediction haywire attack can be very useful, especially since it auto-hits flyers.