Create public Sync ID The reason for this idea is to have a sperate ID you can share to others in order to keep your private Sync ID private and to yourself.
Data Cap To ensure the sender cannot drain the reciever data when sharing data. I know this is already added but to be added as an option per shared folder.
Folder Size Cap To prevent people from trying to send you unnecessary large amounts of data and to prevent unwatched folder growing dramatically in size. Allow users to set the folder size cap in MB or GB units.
Approve Transfer Once you pair two folders to sync they are paired. But an additional step will send you a message approving the sync request once it detect changes in the paired folders.
Once Time Sync Once the files are synced, it will delete the syncthing connection between the two folders making a simple one time transfer.
Folder Expiration Be able to set a date and time when the syncthing connection between two folders will be deleted. Incase you forget syncthing will do it for you.