The number of powers that can be DC pumped is probably about half of the powers that have saves, not including powers that only affect objects.
The psion should get something considering the loss of spell power when compared to a wizard or sorcerer. Augments fill that in nicely.
Just using the class tables (not including bonus spells or PPs based on ability scores) the psion gets 343 points of powers*
Wizards get 564*.
Sorcerers get 726*.
* This is a breakdown of spells into equivalent PPs and uses the Single target Max Damage cap found in the DMG for a 20th level caster. Example, a second level wizard spell costs 3 PPs to cast, and has free damage scaling up to 10 dice (+7pp for free) for a total of 10 points. Note, my math skills are horrid, so while I hope these numbers are correct, they should certainly be close.
When compaired to a wizard a sorcerer gives up infinite spells known, 4 bonus feats, (a free)scribe scroll, and a level lag in learning the next level of spells ---for--- 162 spell points worth of spells and spontanious casting.
When compaired to a wizard a psion gives up infinite spells known, and 221 spell points worth of powers ---for--- spontanious casting, augmentable powers, and a discipline.
When compaired to a sorcerer, a psion has gives up 383 spellpoints, and a familiar ---for--- 4 bonus feats, augmentable powers, a discipline, and no lag in spell/power level
edit: fixed bad math.