This is a suggestion for some plots that only work in the settlement they are in. As an example of what I mean in sanctuary hills there is that one area where the road goes around in a circle around a large tree in the center. For this settlement, you would get a unique recreational plot to turn that entire spot into a small park. In a settlement like the Castle, you get a unique martial plot you can place on each of the corner areas. For some other settlements that may not have some unique features but maybe meant for specific things like farming or water production you could have larger than normal farms that are maybe 4x2 or larger industrial plots that are maybe 3x3 for some of the smaller settlements maybe have 1x1 plots available in them and so on. I think this would help to make each settlement a bit more unique.