Add water so we can make pools in our home. I'd be willing to pay crowns in order to put my own water that I can swim in my home and water gives us many customization options in houses without water... for example the master angler boat is hard to put in many homes as most do not have water.
Dirt and grass furnishings... it's literally everywhere. They would allow us to create our homes in our own image by allowing us to raise the ground floor on our gardens to build on... plus many of us resort to putting trees on stone paths as we cannot cover it in dirt furnishings.
Adding more hlaalu style building blocks would be wonderful. Ald Velothi Harbor comes with 6 hlaalu stone paths but The bad thing is that this may only be exclusive to this home and impossible to gain from other places, they are called hlaalu sidewalk, sillar stone
Add some more blocks like these with this texture to serve as stone platforms as they blend nicely with aid velothi and amaya lake lounge...
Also adding blue tile sets that are used in the roof interior of vivec city would look amazing on my pool and would be a popular furnishing