Really interesting ideas – we appreciate your thoughtful comment! We do know Hooktheory and love what they do.
We are in the midst of some big new projects that are taking our full attention, but we are keeping the things you mention in mind as they are certainly really valuable and would be super useful.
This page is for an offline MOBILE iOS/Android APP version, not desktop/laptop. To vote for a desktop app, see: http://feedback.noteflight.com/forums/4962-tell-us-your-thoughts/suggestions/6796778-offline-downloadable-versionScott commented
PLEASE!!! I'd buy this in a heartbeat!