I would've gone fully instanced.

Multiple areas in the overworld would have entraces that essentially port you to a housing ready environment. The theme of this plot is based on the area, and more "themes" are added as the game expands.

You can own a single house in every possible spot. If there are 20 zones with a plot to buy, you can own 20 homes. All are fully customizable and pricing varies based upon zone. Base areas outside cities being the cheapest, a few hundred k, high level areas like Azys Lla being upwards of a few 100mil.

Group housing still exists. You can have one workshop PER PLAYER and it's seperated from housing. Gardening is much the same, but much more expanded. Meaning, all players, regardless of house status, has access to both.