Something with an alien species that wants to join the borg. Maybe their home system is in a bad way, or they just believe in the Borg’s ideals.
Do you just let them throw themselves in and destroy their society? What about people who don’t want to join? What if them joining the Borg is strategically bad for the federation?
Maybe this was done and I forgot
You don’t even need self driving if it’s mostly just the countryside. That’s just not a lot of people and the resources required to get it working would be better spent on building mass transit and walkable areas in cities where people actually live (and thus where culture and economy actually happen)