I guess a few things come to mind:
- Shotguns are mostly short to medium range weapons, and psychokinesis is mostly short to medium range. That's good in that it gives you full potential in your killbox, but it does leave you a bit weak at long ranges.
- Psychokinesis is mostly strong point damage and weak AoE, and shotguns are mostly point damage with a slightly unpredictable AoE. This means your only consistent targetable AoE will be your grenades.
- Metathermics is mostly strong AoE but moderate point damage, and is mostly medium to long range.
- Psychokinesis offers Force Field for utility and brings crowd control in the form of stuns; Metathermics offers Exothermic Aura and brings crowd control in the form of incapacitation and - with Pyromanic - fears + DoTs.
I would say that either one is very viable, but how you want to play would probably steer you clearly one way or the other.