Making an computer that is fun to fight is a lot easier than a computer that is fun to diplomacy. Maybe with chat bots you could make a computer player that has some semblance of being able to talk to, but unless you are playing with other humans, diplomacy isn't workable.
Is the "with Stellaris characteristics" the part where most players do mass genocide of the entire galaxy?
Making an computer that is fun to fight is a lot easier than a computer that is fun to diplomacy. Maybe with chat bots you could make a computer player that has some semblance of being able to talk to, but unless you are playing with other humans, diplomacy isn't workable.
true, turning the computer into vassals is usually preferable to getting them in a federation