The problem this poses is how would this be implemented? A new method that allows the server to define which player can freely change a property? What happens if I want multiple players to control a property, then how should I know which change is done by which player? How would a developer know which properties are changeable in Studio before runtime?
I think what you really want is some way for the client to change the position of an anchored part on the server for some custom physics system without the bottleneck of firing normal remove events, as implied by your last statement. This could be efficiently done with the introduction of UDP networking, with the advantage of leaving the technical problems posed by explicit replication such as knowing which player did what to the developer, not Roblox.