This would lengthen the amount of time it takes to fill empty plots.
Under the current system:
1. Players A, B, C, D have been camping a house 8 hours. Player E walks up and relocates.
2. Players A, B, C, D locate player E's old plot and 12 hours later, one of them wins it.
Total time a house stands unoccupied: 20 hours
Under your proposed system:
1. Players A, B, C, D have been camping a house 8 hours. Player E walks up and begins attempting to relocate.
2. After 4 hours, player E wins the house and relocates.
3. Players A, B, C, D locate player E's old plot and 12 hours later, one of them wins it.
Total time a house stands unoccupied: 24 hours
This isn't going to be the story with every timer-blocked relocation, but it will be the story with enough of them. Relocation-trains are frustrating enough to campers without making them take hours longer.
Under the current system, ideal relocations are snapped up in minutes, allowing people to return to the game. If a Mist 35 sat open for 8-22 hours with half the server camping it, the lost play-hours from everyone would be incalculable.
Camping itself is a poor system, and a miserable experience. Making every plot a camp every time seems more like a step backward than a step forward.