It's funny...
It's funny how people over-react to things...
Sure, psionic blast is powerful. Yes... it's powerful at 3rd level... IN CERTAIN SITUATIONS!
Here are things that make it balanced
* It's not particularly useful against opponents that are surrounding the psion.
* It's not useful AT ALL against undead, slimes, golems, elementals or animated creatures.
* It's not that useful against a main bad guy if he has a decent WILL safe.
* It's a HUGE waste of pp against a single creature. If you encounter one ogre, it's a HUGE waste of power points.
* The DC is set each time it's used by a random dice roll!
Now granted... for 3rd level, it's a pretty cool thing. And useful for the one encounter a day scenerio. But what if you have more than one encounter and the 3rd level psion is depleted? Then he is useless.
Plus, most PCs aren't really going to get it until 5th level. And at 5th, I'd put it on par with a 6d6 fireball or 6d6 lightning bolt.