But anyway, back to the OP:

Quote Originally Posted by Ernir View Post
Those of you who don't think psionic characters make suitable arcane/divine spellcaster replacements, why is that? As in, if I were to rip out the Wizard entry in the PHB, put in the XPH Psion entry instead, and rename the Psion "Wizard", what is it that would bother you the most? What is it that you would find missing? Particular spells that don't have psionic equivalents, the fact that psions can manifest in armor, or all the crystals psions like lobbing around?
My basic issue with Psionics is that it's a fifth wheel. Pretty much everything that psionic characters can do, magic-using characters can do anyway. Psionics does add an interesting set of new mechanics, but too many of the psionic powers are just PHB spells with the serial numbers filed off and some vague fluff about ectoplasm.

The next problem if you're replacing magic with psionics is that loads and loads of the basic material of D&D assumes magic. For instance, about half the creatures in the various Monster Manuals have spell-like-abilities or powers that directly duplicate magic of some kind, and every single magic item in the DMG and most of the items in the Magic Item Compendium use spells for their effects, creation, or mechanics.

Sure, you can rewrite half of D&D to be psionics-based rather than magic-based, but it simply isn't worth the effort, IMO. The basic assumption of pretty much all the published D&D books is that magic is the base system and psionics is an unusual alternative. There are a few campaign settings and adventures out there where the opposite is true, but they're specifically designed to be different.

So it's not that you can't replace magic with psionics, it's just that I don't really think it's worth it.