I see this exacerbating the housing problem. More houses would be bought for the sole reason of being sold to others. The rich would be ripping off the poor who couldn't afford it at the time. There would also be much less risk in buying houses for the sole reason of using them as extra gardens.

What I would prefer is being able to sell a house at the house's server value, and having the game take a cut out of it. This would allow people to get rid of houses they no longer want, whether it be to move to another house, transfer servers, or simply not enjoying or having a use for their house anymore. It would not be a total loss, and gil would still be removed from the game.