If you'll recall that TNG episode, Kamala the metamorph, was Kriosian. Believe me, I've considered putting her in Gothic's path, but he's got so many women in his orbit at this point it feels redundant and potentially detrimental to the story. It's kind of funny to think about Picard and the Enterprise worrying about brokering a peace treaty between Krios and their longtime enemies when, probably shortly thereafter, the Klingons conquer them. That must have been a kick in the nuts to the Federation. If you're a conspiracy guy, the Federation interacting with Krios might have even clued the Klingons onto them.
_____________
Voluntarily join the Federation as a member or risk the Klingons conquering you in the future.
The Federation offered many benefits to its members, but fear and pain often drove the bus. Not that Picard or others would admit to that cold, ruthless, pragmatic truth, that much of the Federation’s success, why so many worlds joined the Federation, was a direct result of an acute fear of the Klingons conquering them if they didn’t.
There was only one episode in TNG, which hinted at this, where the planet Krios, which had been conquered or subjugated by the Klingons, sought independence from the Klingons and a rebellion had formed to rise up against their Klingon oppressors.