just juice up the current psychic powers insofar as their effects or ranges are doubled/tripled, then halve the LRB difficulties for things like Choke (even quartering it for Telekinesis) and let Eldar WP handle the rest.
Even better, adapt Dark Heresy's power system, because the way people's brains dribble out of their ears when using powers in Inquisitor does not suit Eldar one bit.