Got me thinking that I’m liking this more than what I used to think but with a little tweak.
Reduce the current plots but with the addition of this “landscape only” plots so garnering more plots in total. My version of landscape plots is different though. I want us to be able to put basic blocks in it (so no machines, other crafted blocks, etc.).
The idea is to limit the creation of empty houses/buildings as they are really the one making the place feels like a ghost town since they tend to mean that “there are people living in this house”. On the other hand, through landscape plots, I would like to encourage landscaping and settlement decoration. This can be used for building a floating island, a nice looking statue in the settlement, lamp posts, roads, or even preserved a hill or tree just like what the OP really wanted.
This probably adds complexity to the system but just wanted it to share my thoughts. Hopefully, this will satisfy as well the needs of the builder for more plots without me arguing back that it will just create ghost towns.