I haven't actually delved into the housing market myself, but hearing so many horror stories makes me wonder if it would be better if the current system for buying a house was replaced with something similar to a silent auction.
The price of the plot would become the minimum bid, and the devaluation timer would be the bidding period. Everyone who wants the plot secretly places a bid on it (unlimited maximum bid). At the end of the bidding period the highest bidder is awarded the plot, and if there were no bidders the plot devalues and the bidding period starts again. There could be additional features in place like a count of the number of players currently bidding on a particular plot.
The market would change from being an endurance/luck race to a more capitalist one. Those with more gil stand a better chance of getting houses, but that might not be ideal because it would make it much harder for newer or less savvy players to get houses.
Another alternative that would only remove the "endurance" aspect of housing would be a lottery approach. All players wishing to purchase a plot during a devaluation period can join in the lottery, and when the period ends one random player is selected to win the plot. If no players participate the plot devalues, and players would only be allowed to join the lottery of one plot at a time (can't try for multiple plots at once).
In either scenario, I would see players who already own housing also having to participate in either the auction or lottery alongside those who don't have houses to keep things fair.