Heres the thing, This should be implemented once they fix the settlement performance issues. But this would add more life to the game in my opinion.
Imagine when upgrading settlements through higher tier crafting stations, the whole settlement upgrades and looks different.
Details:
Think about how the armor weight bar works, every stage has a threshold with a certain amount of points to be passed in order to trigger the next stage of the settlement. Each crafting station has a point associated to it. Upgrading stations increases the point value of the said station and increases the bar. Once you have gotten enough points to pass the threshold, the settlement upgrades. This way, you dont NEED to updgrade every station, For EX. Lets say Tier 1 stations=5 pts tier 2=10pts tier3=15pts tier4=20pts tier5=25, to reach the next threshold, and lets just say to reach tier 2 settlement, you need a total of 50 pts, no matter which stations you level up, you can reach that threshold and pass it, so if you have lets say you have a tier 1 station but your other stations are high enough to total to 50 points, the settlement upgrades itself.
What does it look like? Im sure they would have to figure out what looks best, but things like upgrading the material type of the structures, and the architecture of the buildings to look more advanced would be amongst the visual perks for upgrading.
Additionally, they could change certain details when doing this. The town board would give more appropriate missions to fit the type of settlement youre in. Not a 100% knowledgeable about how the upgrading works for invasion camps, but they can incorporate the different tier settlements to structure HP and weapon damage.
As usual, any additional feedback is welcomed, I just want the world to feel more impactful on a more detailed scale.