Hey all, I'm looking for some advice regarding a homebrew psionic class I'm trying to make for my dark sun campaign.
I was hoping to base it off of the idea of elemental control that some people claim to have through sheer thought power. My idea would be for it to be a striker with secondary focus being based off of an element u control. I was thinking pyrokinesis could be leaderly, cryo could be defender, and electro could be controller. I realize creating powers and secondary effects could be a lot of work where I could just re skin the elementist, but I just don't see the elementalist as particularly effective.
some problems I face are creating an effective yet unique striker feature. I thought maybe just baking damage into the powers or giving some sort of temporary boost when enemies are bloodied or die, but I'm not sure.
Also, determining ability scores has been an issue. I wanted to make an int primary striker, but I feel that would be too similar to psion in terms of flavor.
any help, ideas, or advice are greatly appreciated
ps: if it helps, my influence for the class were characters from inFamous aswell as The Phoenix from xmen
Why is this psionic rather than an elemental class?
I'd consider making CON its primary. Not for any real reason other than there's seriously few CON-based classes. Also, you could rationalize that for an interesting elementalist class. The awesome fortitude it takes to deal with such powerful elemental energies, and control a summoned elemental, etc. I just say that because if I were to build a class, I'd make it CON-based first, and work from there, lol. Secondary ability could be INT or even CHA.
One nice way of making it a full striker is have it summon an elemental, but use a minor action instead of a standard action to order the elemental to attack, then, you could essentially get two attacks per round for its striker damage. Said attacks could be a slam from the summon, and either a ranged shot from the PC, or a elemental damage melee attack from the PC. Mechanically, it could work a lot like the beastmaster ranger heavily refluffed with elemental damage and bits of elemental crunch toppings. 
I could see it as psionic, primal, or arcane, personally...That all depends on flavor. If you want the class to have power points, obviously psionic. It could attack via a summoned elemental as its unaugmented at-wills, with PP's spent to amp power up...Or, go the other way; PP's for the summon. Hmm. I prefer PP for the summon, and at-wills and dailies doing ranged or melee elemental damage. Then you'd have a cool striker, with a PP summon you can flank with, and your allies can flank with too.
Again, though, it doesn't have to be psionic powered. If you really want it to be, that's fine, of course, but, then give it PP's. It bothered me enough that the 4e Monk didn't have PP's that I re-wrote the class to have PPs (aka Ki points). Although, I thought it was genious to make the Monk a psionic class instead of a martial one.
Interesting idea, though. I might give it a crack sometime if I feel like playing with 4e mechanics. (Which is often, as I love them, and understand them better than any other edition.)
Thanks for the idea I liked it and can see going int con or wis con. I like the idea of creating an elemental, but still on the fence. In my mind I imagine it more like a caster or Gish like class, but why not mix them? As for why I chose psionic, I used Jean Grey and the conduits as inspiration, and while I loved the monk, I feel like a pp striker would be interesting
Ok then you want psuedo-scientiffic energies not classical ones.
Pyro and cryo for example are basically the same power under the pardigm you described. Really good for controller since multi-targeting is a major part of this archetype.
Electro works fine, also has a magnetic component (paragon path maybe?). This is good for a pure striker but could also have leader applications.
Photo-kinesis is another good one, great for disabling and visual trickery.
THis kind of limited power set would allow for more advanced training outside their powers, I'd suggest considering tis might work better as a set of intensive darksun style themes than trying to tie it all together with a class.