Another suggestion!:
The ability to trade a plot to someone!! So sick of seeing people have to drop double the gil to get a SMALL plot because the person can only "relinquish" it and not "sell" it to someone. If we could trade or sell plots (with the game making it automatic to the value of the plot or not), this would give people who bought a house but don't use it the chance to recoup their costs, thus being more willing to give up the plot to someone who will actually use it!