I love psionics but I'll make this short.
What does Psionics mean to you?
Enlightened monks, Ancient orders (Jedi), other worldly mystics (Cthulhu)
It puts me in a different mindset than playing a mage. It has a different feel and the "feel" is the main reason I'm staying with 3.5 so yes thats very important to me.
How can I get you to buy a psionics book and use it in your campaign?
I lkie this:
1) Take the existing 3.5 psionics rules.
2) Actually playtest them. In a big, open playtest if necessary*.
3) Plug up all of the infinite-this, nova-that loopholes.
4) Remove unnecessary redundancy. (Psionic item creation feats, I'm looking at you.) I also like:
"Mindblade should probably be a feat line."
But lets face it if you make I'll probably buy it and if you don't I'll use what i have (3.5).
What is an absolute deal-breaker?
Making the system like a mage variant.