Even with the current system they could have made more effort in some cosmetic customizations.
For the workshops, have different types you can select. One is the current mill, another would be a kitchen, a smithy, a furniture workshop, alchemist lab and so on.
Then for the granaries it could be a storehouse/barn, or a toolshed with mining or woodcutter tools.
For landmarks, have a personal house around the size of a single plan small house. Give us 3-4 versions of it with different layouts of furnitures and design.
For current landmarks, give us versions. Instead of a bathhouse that seems to draw more from SHB dwarf style, let me have one in a Sharlyan or Lominsan style.
This could make for more varied islands while still using the current system.