I would like to see anothers colonist building their own base, instead of just raiding. When they appear, thats is your choice to raid them, leave them alone or just go talk with for alliance vs others raider or resssource. They still could just appear and start raiding like now. But would be nice some variety.
It would be cool if the raiders made a temporary base before they send out scouts to find you, and when they find you they might start harrasing you, or sabotage your equipment, when they feel confident enough they will either attack or send for reinforcment . If you don't want the raiders to attack you you can move in to smash their camp instead. Do it when they are still weak,
Sounds like something to send a fleet of domesticated boomrats at. ::)
After you had your cowdisease stricken muffalo's trample there walls down