That would be a nice alternative, since implementing own user profiles with proper server structure is not trivial (or free) work.
Would be difficult to support every cloud provider, especially if each one has its own API and they don’t play with regular files, but with exotic formats - like new Android for public storage.
Google Drive seems a nice first candidate since all Android users have automatically a Google account and so access to the Drive.
Nevertheless it’s a “nice to have” feature and I could consider it after more of the core features are implemented.