If we had the ability to enable/disable the syncing of objects, and choose who syncs with what data set, then we'd be able to implement some type of interest management for our multiplayer games saving on bandwidth.
In order to create a secure multiplayer game with the multiplayer plugin, we would need one client, that is always running, to act as the server/host. Right now, there is no way to manage having a single host run the game efficiently on multiple layouts or really large layouts, due to the Sync function always being on and active for every peer, regardless of which layout they are on or how far away they are from other peers, using up bandwidth unnecessarily.
As a result, multiplayer games made using the multiplayer object limit themselves to peer-to-peer hosting which is open to exploits, or to peer-to "dedicated host" where the host can only run one layout per browser tab. This doesn't work well if you need many empty/open rooms at a single time, and it just seems kinda silly.
I think the lack of flexibility around the Sync feature is the main reason why the multiplayer object has yet to be used seriously.
If we can toggle Sync, and choose which peers to sync data with and when, then we can target certain groups based on their layout or distance, and circumvent these issues, enabling us to create open world multiplayer games.