No questions asked, dreaming allowed?

Proper instanced housing. No, not the cupboard under the stairs Harry Potter shit we currently have.
  1. every character above a certain level and MSQ progression is eligeble for housing. That includes alts.
  2. you choose a location first which is not limited to the main cities but can also include areas like Crystarium, Ruby Sea, Dravanian Forest etc.- the locations don't have a limit on how many players can choose them and if every single player on a server wants their housing in Ruby Sea, that's possible. It's also possible to change location although maybe with some restrictions.
  3. you start with a smaller house and plot and upgrade it through a housing instance specific questline all the way up to a mansion (if you want)
  4. through the questline you can also customize the garden size (e.g. combining a small house with a large garden), garden layout (making it longer, attaching it to the back/ front/ side of the house etc), the layout inside (e.g. where stairs are, pillars, windows, door placement etc). You may now simply delete pillars and windows completely. You're welcome.
  5. the housing menu lets you float items as well as turning/ flipping them around all axes. If you want to flip that table upside down and make the house look as if someone just robbed it, go ahead. Or use the underside of that indoor waterfall to create oddly shapes stone stairs. Items can now be floated into the ground so only part of them peeks through the floor as well
  6. when placing an item you can tick a "item disappears through walls and floors" box which allows you float items through the ceiling if you want to use the underside in the basement without the top peeking through the main floor
  7. the item limit is greatly increased, probably low 4 digits
  8. stable, mailbox etc. are now features you can turn on/ off any time without them taking up a slot
  9. you can put minions anywhere in your instance and either set a limited area where they roam or leave it completely up to them and have a Shoebill giving you a hard stare from across the instance
  10. the housing menu has a "placeholder item" feature which allows you to place an item without owning it and see it with the full texture but it appears plain white/ grey to any visitors so people have a reason to buy/ craft furniture but can still experiment freely with full designs without crimetooling or crafting/ buying a bunch of stuff that didn't look good after all. Once you acquired an item you can choose to replace a placeholder item that you already placed, saving you the hassle of moving it in the exact spot again
  11. the housing menu has a "save layout" feature which allows you to switch between a few designs you finished as long as you have all items in your housing storage (which is also expanded). When chosing one a list of items is shown and anything that's not in the storage is marked red so you know what to put in for a quick switch

And before someone says that it's too unrealistic, no game could possibly do all that... all these features are in other games. Some even have the majority of them all at once.