Honestly?

I think a lot of these problems go away if...

1. Move Workshops to the Grand Company; relocating all your exsisting vehicles to said workshop as a 1 time deal. In the future you can have as many as you want but the cost for additional "slots" is exponential; either that or simply kill sub farming.

2. Allow ALL buildings to have additional chambers..many as you want again with a exponential gil cost attached.

This will help remove some gil from the overinflated markets and frankly give folks something to spend gil on.

3. Double all housing item limits - Small 400 - Med 600 - Large 800. This will make a lot of sense especially if you've ever tried doing anything elaborate with a large that didn't involve giving up a few rooms; generally because the break it down stuff uses sometimes like 20 items for a doorway. A lot of "larges" are just a really fancy bungalow like build due to the item limits allowing designers the needed creative leeway. This will increase the desirability of Smalls.

4. Provide more then 1 layout option. Currently all houses are inside a CUBE but why not a rectangle? Or hell a cylinder! Rather then a small having stairs to a basement...why not a attic? Or perhaps a 2nd room though a hall from the first? Again have a architect permit cost of a 100k or something?

5. Limit accounts to 1 FC master 1 Personal per world; if you are in excess you got 45 days to find a master for any house you do not flag as "yours" - this largely depends on the aforementioned Workshop change above. Yes it means some folks are going to lose houses.