Hey Tony 
It has been a while since we last chat. On such an interface I would like to:
- be able to (un)mount from a root directory
- see all my available services
- sync my directories per service
- sync my files per service
- maybe see some useful information about each dir/file on a service (i.e. is my object in Glacier in S3 or not, because otherwise, I’d be not able to sync it obviously)
- remove my synced files only locally (so the placeholders appear)
- remove my synced files from both locally and remotely
- share files/folders
These are the very basic which I can do with ResilioSync easily, you should give it a try (there is a free version and trial version) just to get some idea about a useful interface.
I’m happy to give feedback and ideas to improve this product (which I am obviously now paying for).