I agree with all of your suggestions. There is a whole mess of stuff that should be added, and the floating trick should be easier than it is, in fact- it shouldn't be a thing at all as things should just float if you want them to float with an option like rotate or reposition. Wildstar had THE best housing system in any MMO and I miss it dearly due to the extreme limitations given by Enix. I know they see the float trick, yet have yet to implement something that gives us an easier option to do it. I think add a float and sink option.
What I would like to see item wise is bird cages, hanging plants, more indoor fountains, the ability to change the molding and stair material, just to name a few.