So there would'nt be magic or [censored].
Flameballs could also simply, and more likely as flamethrowers.
Of course, ordinary people would refer to psykers as mages and their powers as magic. So, psykers could wear mage robes to increase their influence and authority.
In a way, there's no difference between psychical powers and magic, except in limitations.
Frankly, psionic magic would be a really great addition to the Fallout ip. I was very disappointed with Fallout New Vegas. While the original Fallout had the Master - which was awesome and wacky, New Vegas only had two boring human factions fighting for power. It's like Obsidian can't create anything really cool. The same was with Fallout 2 - they couldn't create a cool villain like the Master and had only ordinary humans and a boring mega-boss super-soldier.
It would be great to have some kind of a wacky psionic monstrosity as a final opponent in the next Fallout game (preferably not developed by Obsidian).
Similarly psionic elf mutants would be a great new faction that could be as interesting as the old Brotherhood of Steel.
Or different types of psionic mage mutants evolving simultanously and forming different factions with different worldviews. It would be awesome and would bring back freshness into the Fallout setting.
It could also have a psionic powermaker similar to the spellmaker from Daggerfall. It would add a lot to the gameplay. Also, the sudden evolution of part of mankind would add interesting new ethic dilemas.