Right now it’s a pain to navigate the world using both the slice-world view and the transparent walls and still you can’t see through floors of buildings.
My suggestion is that the view should be locked to a specific z-level and you should be able to switch the z-level with a key or scrollwheel.
Think Dwarf Fortress with TWBT Multilevel.
You should always see things under your z-level but everything blocking that view above should be cut from view.