Another cool idea would be to have another type of settlement requests: search(or something much cooler). In this mode, a synth is hiding among one of your settlements, and you have to go throughout your settlements, trying to find the synth.
Lastly, like everyone else I would love way more settlement options. I played the main story line, and tons of side quests. I got as far as tracking down a special synth (not the detective...) and tried to go back to the quests but always got side tracked by building. I learned one thing: building is tedious. However, the thing that kept me from building large settlement is the components required. So, a new mode where you get unlimited resources and accesses to all perks (w/o being able To get trophies, of course) so that we can just build. And a terrain mode. Dear god include a terrain mode. I'm so tired of my fences half floating in mid air and half on the ground. It kills the immersion. A smooth way to incoporate this is to have to collect shovels and pick axes to modify the terrain. To pair with this new feature they should add some new pieces, like the institute pieces, pre war pieces etc. or even a polished set of items. You have to admit, it is kinda weird that you break something down to its purest form, then when you reassemble it its rusty and whatnot.