If all plot's were equal and if all Residential Districts were equal then I would agree, but they are not. The Goblet is my least favourite district and if an opportunity arises to move elsewhere I would. If I moved to The Mist and then a month later Shirogane opened up, I would be there in a heartbeat.

I doubt the majority would be plot jumping as described. Everyone who owns a house should be able to upgrade their plot location as they see fit as it's not free. The problem I see it is with the timers and there have been plenty of threads on those.