I generally allow one player per party to be a psion, and it's always the one I trust the most to be reasonable with it. I've never had issues with it being abused, because Traveller psionics are fairly self-limiting. The protective powers don't make you anywhere near bulletproof, the offensive powers aren't more threatening than a trained sniper, and the utilitarian powers are frequently useful to the party as a whole. Even having allowed the non-world-shattering Advanced Talents from the Psion book (because yeah, screw time/dimensional travel, that's a campaign breaker), the biggest thing that my current campaign psion has done was incapacitate a pair of station guards in combat armor while in the open without anyone realizing it was her doing it.
In addition, it opens up a lot of opportunities for adventures that wouldn't normally be doable. Right now the party is on a planet that's started to death-camp its psions because elements of the planetary government always hated them and their new status as an Imperial client state gives them the excuse they always wanted. Naturally the psion's mentor, who was established at the beginning as an Ally, is there, and needs help getting 200+ young students of a psionic institute/boarding school off-planet. The fact that this planet has Quisling telepaths who were promised a comfortable home on another planet rather than extermination, as well as imported alien psi-sensitive hunting dogs, means that this character must always be extremely careful, wearing a psi hood and using the aura masking abilities to hide her talents at every checkpoint.
Not to mention blatantly cutting out psionics from the OTU kinda neuters the Zhodani entirely. You could always just never bring them up, or restrict psionics to them, or just say "there ARE psionics but YOU never will get them", etc, but that's no fun to me.
In addition, it opens up a lot of opportunities for adventures that wouldn't normally be doable. Right now the party is on a planet that's started to death-camp its psions because elements of the planetary government always hated them and their new status as an Imperial client state gives them the excuse they always wanted. Naturally the psion's mentor, who was established at the beginning as an Ally, is there, and needs help getting 200+ young students of a psionic institute/boarding school off-planet. The fact that this planet has Quisling telepaths who were promised a comfortable home on another planet rather than extermination, as well as imported alien psi-sensitive hunting dogs, means that this character must always be extremely careful, wearing a psi hood and using the aura masking abilities to hide her talents at every checkpoint.
Not to mention blatantly cutting out psionics from the OTU kinda neuters the Zhodani entirely. You could always just never bring them up, or restrict psionics to them, or just say "there ARE psionics but YOU never will get them", etc, but that's no fun to me.