Nifft
Penguin Herder
The primary weakness of Psionics is the lack of Wands of Cure Light Wounds. 
Rangers, Paladins, Bards, Rogues (with UMD) and Druids can all do out-of-combat healing, at a cost of 15 gp per 5.5 HP of expected healing (~2-3/4 gp per hp). Psionics has no such bargain. (And that's the price if you buy the wand -- the party can make them, cut that in half.)
Ooo, forgot something:
Dragon Shaman: The Fast Healing aura is a great complement to using Psionics to patch up after a fight. It's not a strongly magical class, and you could easily substitute Psionic powers for their spell-like abilities. It does a decent job of filling the Cleric's role without being a Cleric.
Cheers, -- N

Rangers, Paladins, Bards, Rogues (with UMD) and Druids can all do out-of-combat healing, at a cost of 15 gp per 5.5 HP of expected healing (~2-3/4 gp per hp). Psionics has no such bargain. (And that's the price if you buy the wand -- the party can make them, cut that in half.)
Ooo, forgot something:
Dragon Shaman: The Fast Healing aura is a great complement to using Psionics to patch up after a fight. It's not a strongly magical class, and you could easily substitute Psionic powers for their spell-like abilities. It does a decent job of filling the Cleric's role without being a Cleric.
Cheers, -- N