my personal reward for building killing never ending stream of would be looters and taking their stuff.

dragons in skyrim come to mind.

All I know is that I'm gona set the freakin merchant with the weapon schematics to essential as soon as they publish the editor....

Well, if you want to talk incentive for settlements, let's go back to why you built the place to begin with.
ask anyone who plays games like City: Skylines what the incentive is. And usually the answer is...there is none. I started it, I live there, I want it to do well.