Hmm, never done it, but here's some things you want to think about...
1) Healing. While XPH psionics offers some limitted healing through Empathic Transfer and Body Adjustment, this is a lot less than what Clerics, Druids, or even Bards or Paladins can bring to the table.
2) Converting minor spellcasting classes. The major spellcasters (wizard, sorcerer, cleric, and druid) are certainly gone in an all-psionics campaign, but some of the archetypical classes of D&D are minor casters, and you might want them to stick around.
If Paladins and Rangers are reasonable archetypes in your campaign, you'll probably want to turn them into non-spellcasting variants.
Convering the Bard, a sort of mid-major caster, is more difficult; probably the class needs to be rebuilt as a psionics-using class with something like the psi-warrior's progression and a different power list.
3) Other things psionics are bad at (relative to arcane or divine magic) are going to be hard to do. Psionics aren't good for buff effects cast on others, or illusions, or necromancy just for a start.
1) Healing. While XPH psionics offers some limitted healing through Empathic Transfer and Body Adjustment, this is a lot less than what Clerics, Druids, or even Bards or Paladins can bring to the table.
2) Converting minor spellcasting classes. The major spellcasters (wizard, sorcerer, cleric, and druid) are certainly gone in an all-psionics campaign, but some of the archetypical classes of D&D are minor casters, and you might want them to stick around.
If Paladins and Rangers are reasonable archetypes in your campaign, you'll probably want to turn them into non-spellcasting variants.
Convering the Bard, a sort of mid-major caster, is more difficult; probably the class needs to be rebuilt as a psionics-using class with something like the psi-warrior's progression and a different power list.
3) Other things psionics are bad at (relative to arcane or divine magic) are going to be hard to do. Psionics aren't good for buff effects cast on others, or illusions, or necromancy just for a start.