I think Psionics should be more then just mind control. One thing they should emphasis in my opinion is mind tricks both as a buff for your own (imagine seeing a charging soldier who thinks he is the king of the world ) or debuff the enemy. Having it as a utility skill with gimmicks is more useful for humans who relies in versatility against the vastly superior specialized aliens. Let the aliens keep their mind control and give us something more fun. Perhaps personal levitation or the ability to throw grenades with your mind (basically not have the throw limited by your line of sight)