I was totally hoping cryokineticist was going to be at least as cool as pyro, but then that entry requirement quickly kicked that hope in the balls until it died. Pyrokineticist is for ex-monks. They have the concentration ranks, and they have no ability to continue being monks once they fall off the enlightened path. So Spellfire Wielder and Pyrokineticist are their best bets for advancing Something. In the case of spellfire wielder they can become potent anti-magic jerks, because evasion, high monk saves, draining magic items of their enemies to fuel their powers. With pyrokineticist they have to fall to a chaotic alignment, but by the time they're setting fire to a structure to watch it burn, that's probably already the case.
Sure, the monk doesn't have a full bab, and neither do the other two classes, but with monk based grappling the spellfire channeler (not wielder, I think that's the name of the feat) can disarm opponents or rub up against them to drain their magic items, while sucking down some levels of pyro will give them a much needed offense for the times when they have no magic juice to spray all over their enemies in contempt. Both classes offer fire (psychic fire, or super arcane fire repsectively). And if the monk started out as a psionic race (such as a half giant) they already meet most of the requirements of pyro by 5. If they still aren't chaotic by then, they can fall off the monk path with spellfire channeler levels and then jump into pyro whenever they reach chaotic (burning **** down with spellfire along the way should help that).
Anyway...in response to Forrestfire about Complete Psionic: Don't forget the illumine blade. That class is amazing for killing undead, and always super helpful for even just the capstone: 1/day when you hit 0 hp, you heal 5d8+5 hp instantly. It's what kept my soulknife/illumine blade/soulbow alive multiple times across a long campaign. Hell, that and refreshing death ward for expending psionic focus was great. Mmmmmmm, basically permanent death ward. Even if it got dispelled, it was up again next round.
I think I'll go with complete psionic as being the thing that broke my heart in 3.5. It was basically less than a handful of useful things and a lot of bad filler shoved into a book and published at first read. And I bought it. Oh, I bought it immediately, because wizards had such a habit of basically ignoring psionics for 3.0/3.5 for so long that by the time it came out I wanted Anything that was an official psionics book. The good things from that book could have been put up as mind's eye articles, but I suppose the best part about that book was that it was a published book and thus legitimate in the eyes of the person who was gming that campaign I was playing a soulknife in. If they had been mind's eye article classes, they would have been rejected out of hand.