How is that an issue? Relocating frees up the old plot. Yes, it goes on a timer as well but it will become available for purchase at some point.

If you're thinking you're going to be able to directly buy one of the more desirable plots, you're likely to end up disappointed. Most players are willing to pay that little bit extra to buy whatever they can cheap so they can move to where they really want to be as soon as it's available.