There are two massive problems revealed by the current system...

A. User interface and graphic wise, plots that are on the cooldown timer look identical to plots that are actually available to be purchased now. I had a blast running around last night trying to find a plot that was actually purchasable and never did. This is likely what is causing players to camp these things so hardcore. This is a disaster implementation from the UI side.

B. Houses left over from relocation should probably have some expedited cooldown timer, if none at all. I get the need for the cooldown for relinquished plots because you don't want people selling these things off for cash. But someone relocating isn't likely selling the house/trying to flip it for gil. As it is now, players who relocate are (unintentionally, no fault of their own) causing havoc for people just trying to get a house because some houses look like you can buy them but you can't and they get stuck on a cooldown. This will continue to be a problem, because if and when SE adds more housing, this issue will resurface at probably a larger scale (especially if say, a new district entirely is released and you see a huge migration).

In short, the current system really sticks it hard to people who don't have a house.