What I'm interested with psionic classes is how they'll deal with previous psionic ideas in previous editions.
Psionic Focus: Was described as being one of
WotC's early attempts at having encounter powers. Could be in, but might be too complicated with the whole Maintained/Expended Focus dichotomy everything had.
Attack Modes: I'm 95% sure that most of the psionic attack modes will be At Will powers.
Power Points: Probably out of the system now, based on how powers work.
Crystals/Snot/Ectoplasm: Probably in, because it's something unique for psionics, even though it doesn't match a lot of people's ideas on what psionics should use.
Dorjes/Psi-crowns: Possibly in as "psionic implements", but then again they were "psionic-X" versions of wands and staffs, so they could be out.
Mantles/Auras: If there's an Ardent/Divine Mind 2.0 these might be back in.
Soulknives: Probably will be in, in some form, since the imagery of soulknives is something that
WotC probably wouldn't want to give up.