1) Celerity momenta give Mind over matter mastery.
Reasoning: celerity is about momenta - getting momenta should raise the corresponding mastery.
2) Displacement spell have an additional effect: when nothing is probed, it passivly increases avoid hits.
Reasoning: To make it useful not only for high mana-pool casters; also, the bubble spell already links the user mana to hps - repeating!
Description-wise - the spell help text can say something like that: the psionicis can force fluctuations of the air density around the caster making harder to see him/her for the enemy (reasonable from physics perspective

3) Add floating disc to spell teached in the guild (obviously the right place)
4) Since many come for celerity alone, could telekinetic thrust
spell be upgraded: E.g. it could have a critical effect Or the bounce effect (hits several ebnemies)? Or swarm effect? Not much overpower but at least more fun to cast to grind the masteries.
The swarm could be affected by multistrata mastery - now it raises by casting the thrust spell by the way

Thanks!