I'm slowly plodding away at a project I haven't announced yet, and likely won't until I have more of it finished. One of the things that it requires is a system to handle psionics.
My initial idea was that I would use the SRD to recreate the algorithms in AD&D 1e. As I investigated it I realized that not only had I never really read the 1e psionics rules, but that mental combat had already begun in just trying to figure out how it all worked!
I played a lot of 2e back in the day, and we did use psionics in that, but the system was much simpler. So I went back to the source with the OD&D and found psionics to be even more convoluted.
This is all probably one reason why most people didn't like or use psionics to begin with.
I don't like the 1e psionics system for several reasons. One reason is that psionics is far less effective against non-psionic characters. So if you incorporate psionics in your game, even if just for monsters, most characters will not have psionics in the first place, thus handicapping your psionic creatures. I don't like that a lack of psionic powers actually grants a form of immunity to psionic attack.
Another reason, and probably the biggest, is that 1e (and OD&D) psionics is a LOT of book keeping and needless point exchanging. You see, with 1e psionics non-combat powers only cost one point of psionic strength, of which say an average character will have 70+ to as much as over 150 points. Given that with complete rest a character can recover a lot of points per day, this makes point expenditure needless. You will never run out of points anyway.
Psionic combat in 1e is another matter. The combat powers do cost more points, as do defense points, but opponents could fight several rounds before they have broken through defenses and finally do something useful. Say 10+ rounds (if each side as an average amount of points) of playing with each other's points. This makes psionics sort of pointless in combat since most of the butt kicking will happen in the first several rounds of combat, and if your character is sitting around not doing damage or something else useful for 10 rounds or more, he may as well not be in the fight. Not to mention that all things being equal, say when opponents have about the same points available to them, by the time an attacker breaks through defenses he won't have any points left to attack anymore!
So, what is the solution? I think the best course of action is to revert to a simpler system that is not point based. If I'm going to do that, I'd like to keep the system compatible with my previous work. So I think I will port over the mental combat system from Mutant Future, and treat psionics in the same way as mutations, so that they will be cross compatible. This will be convenient because I can envision this book I'm writing as something someone would use as inspiration in creating campaign worlds for the Mutants & Mazes aspect of Mutant Future.
For people unfamiliar with mental combat in Mutant Future, it is essentially a test between opponent's willpower ability scores, so that when opponents with equal abilities pair off, the attacker has a 55% chance of succeeding. The probability is adjusted in either direction by 5% for each ability point difference higher or lower between the opponents. In Mutant Future all of this takes place using a d20, so an attacker with WIL 15 against an opponent with WIL 13 would need to roll 8 or better on 1d20 to succeed.
An interesting thing about this algorithm is that while it is used in Gamma World 1e, it is also used in the Basic Roleplaying System (Call of Cthulhu, RuneQuest, etc) where it is call the "Resistance Roll" and uses a d% instead of a d20 (also the percetage is 50% when abilities are the same), but the overall probability increments are the same. When I noticed this it made me wonder whether one game borrowed from the other, or whether these algorithms were arrived at independently. In either case it is a system that works very well.