Well, it would depend on the AI. Most computer players go for complete extermination, but some of them seem happy to accept surrenders. They do tend to attack homeworlds on first contact though, so I'm thinking a "primitive" AI would hope to encounter a human player before a computer one.
It would be interesting to see how people treated the primitives. For example if I encountered one in my space and I didn't need the population/ planet too badly I would probably get a treaty with them and let them live out their lives independently in the shelter of my empire. (assuming the win conditions allowed it). After all, they're not hurting anyone...
Sometimes I think I'm too nice to be an megalomaniacal interstellar dictator.
***Something else just occurred to me - Once the hard work of creating a "primitives" mod was done, creating primitive races would be easy - no shipsets, no ship design files... just a race portrait, an army graphic and some work on the diplomacy files.
I might have a go at this mod - S_J, do you mind if I use Pirates and Nomads as a template? I'm new to this modding lark
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"Pinky, are you pondering what I'm pondering?"
"Uh, I think so Brain, but how are we gonna teach a goat to dance with flippers on? "