I've been reading the rulebooks and handbooks for a while and one thing doesn't stop to bother me - INT is always mentioned as Psion's most important attribute, yet unless you want a Shaper psion, you need to invest into something else (like DEX for Nomad and CHA for Telepath). It seems a little bit contraditory to me since those sources tell me that INT is the reason a Psion can cast at all and has all those bonus PP because of that, yet somehow high CON of Savant gives him all the PP and manifestations. I've got that if the attribute is 9 or lower you can't manifest any power with that attribute (even with Expanded Psionics), but the rest seems illogical to me. Can anyone explain this, please?
There are two different varieties of D&D 3 Psionics.
The 3.0 Psionics Handbook gave Psions a different key ability score based on their specialisation. Nomads used Dex and Telepaths used Charisma for instance.
In the 3.5 update to Psionics, this was changed so that all Psions used Int as their manifesting statistic.