I propose a two layer system. First layer is intangible objects, namely, objects you can walk over/through. Second layer is tangible objects - these are solid and act as barriers. These layers work with each other to allow more GH customization.

Rugs, creature entities, certain lights, and many other objects could be categorized as intangible. Pretty much everything else is tangible.

Intangible entities could be placed anywhere there's a flat surface with space. They would not be limited by the current placing system, which protects players from blocking themselves off from important things like the command console. I would say that any furniture, including other intangible furniture items, could be placed on top of intangible furniture, but then you might have to get super weird with the coding. And people would stuff a bunch of snipes in the same square so they'd explode out of each other as a snipe bomb whenever the hall loads.

.........

Maybe limit this to just "you can put your table on your rug. Happy?"

Summary: Let us place furniture items that do not block us off anywhere there's room, while still keeping the "don't screw yourself over by blocking yourself from the command console" limitations for tangible items we currently have.