How about a Sync service delivered directly by AgileBits? This would make the Dropbox/iCloud crutch redundant for syncing multiple devices with different operating systems and would give us a pure sync option instead. Directly from the makers of this great software.
This of course could be offered optional to the existing sync methods for a small monthly fee. As long as security aspects are considered thoroughly I would be a paying customer at once as I hate using my Dropbox for password syncing (Windows, iOS, OSX and Android). Just a thought :-)