Artificers use intelligence, right? Anyway, 'that there is not enough classes using it' is a poor justification, they should use the stat which makes most sense and of the mental stats int makes least sense. If think about some sort of meditating mystic that unlocks the higher levels of consciousness to tap on supernatural abilities then that's clearly wisdom, if I think about some sort of rasputin-like mesmer then that's charisma. I don't know what intelligence has to do with psionics at all.
LOL

Artificers... right.
Anyway:
CHA: Bard, Paladins, Sorcerers, Warlocks = 3.5 classes
WIS: Clerics, Druids, Rangers = 2.5 classes
INT: Wizards, Artificers (again..

),
and EK, AT = 2.67 classes (sorry, I
don't include Artificer--worst class ever IMO, but for this... fine.)
Maybe have the powers split about 40/40 INT/WIS and 20 CHA?
Finally, INT makes the most sense for many of the powers you have, WIS is definitely right for others, and CHA is probably the least used IMO, but still has a fair share.
I don't know what intelligence has to do with psionics at all.
Telekinetics is all about INT-- mind over matter. There is a
reason why INT has been the strongest factor of psionics since the beginning.
Anyway, 'that there is not enough classes using it' is a poor justification
No, it isn't. Maintaining balance and usefulness of all the ability scores has been important for many games and for many tables of D&D, which is why we (as a community) have
so many house-rules to try to make STR and INT (and even CHA a bit) important for the classes whose core features aren't depended on them.
I'm not saying each ability score will be equally important for every PC--
that wouldn't make sense. But using INT makes just as much sense as using WIS or, gods forbid!
yet another CHA-based class.
