hmm. I think there should be a will over reality flavor, and intuition powers, which would be like divination. For example, in battle, a mind user could intuit an opponents' attacks, have a powerful 6th sense to detect surprise attacks.
I wouldn't like having to pick one path and being barred from others. Maybe Psionic could be a template that then classes could work from. I try to picture things that it would make sense or be cool for a psionic to do.
One major flavor I think would be that this guy should know stuff that people are like how the heck does he know that, how can he pick up on stuff so well, he is a genius, he has a natural ability that others don't have.
Well, here is some stuff I had just jotted down off my head for a psionic rogue type:
Rogue/Psionic
This Rogue uses Psionics to make her sword-fighting equal that of a skilled fighter, gaining advantages against multiple opponents. Her powers also enhance survival functions, like healing wounds and using skills.
Weapons: (example) two kodachi, throwing knives, kusari-gama, etc.
Armor: NO: Instead of armor, has dodges, uncanny dodges, evasions, mobilities, two-weapon parries, wisdom bonus 6th sense intuition to AC (like a monk). Has training with peicemeal, like bracers, just nothing encumbering.
Special: Initiates enduring psionic effects, often area effect emanations, to complement swordfighting, often unbeknownst to her opponents.
Examples:
-Affects opponents' perceptions of where she is (forces an illusion into the mind) so it appears she is teleporting and attacking from all around (concealment bonus, sneak attack bonus). They attack where she is not, and she attacks from where they think no one is.
-Causes opponents to perceive painful shocks from her parries, or a sense of getting weaker or dizzy as if poisoned from her cuts, or as if her weapons had some other magical ability.
-Manifests or increases her 6th sense intuition for defending/attacking, telepathically (or maybe clairvoyantly) intuits opponents' attacks before their bodies move, senses invisible opponents, detects arrows coming from behind, etc.
-Enables use of her weapons as extensions of her body/mind, negating the penalty that otherwise makes 2-weapon fighters seem like they can't hit a barn wall.
-Affects time or space for advantages to speed or travel (haste, dimension door)
-Affects her body, releases strength limits on her muscles, or whatever.
-Willfully reverses damage done to her body or causes fast healing, rapid cell multiplication, forces poison out.
-Unbalances opponents with telekinetic mind shoves to create openings, or just grabs the throat and hacks away.
-Telekinetically armors her skin or uses her will on her cells to prevent it from wounding easily (damage reduction)
-Increases stealth: Affects passerbys so they can look right past her and not notice her unless really trying to.
-Can make it so an unsuspecting target does not feel her pick pocketing or sense her near him.
-Can telekinetically run up walls
-Can radiate friendliness or intimidation
-Can sense minds of people trying to hide or minds in secret rooms behind secret doors
-Can telekinetical dissarm or set off traps
-etc. etc. long list.
-At higher levels can willfully summon monsters or elements, crush people, dominate minds, willfully effect reality....
I don't know, I just try to picture some stuff and think, well, this character should be able to do that, they have mental powers others don't, their willpower affects reality, other's minds are open to them to affect, their minds are aware of things that others' minds are blind to, things like that. Yeah, wizards ought to be wary of these guys, they have a formidable power source that really makes them dangerous to deal with.