Do you really think this app will still need major work 5 years from now? As I said in another comment, work on version 2.0 (since 1.0 is probably not complete now) and put it in maintenance mode then, instead of cramming it with useless features.
Idea: flat charge to export the entire library to a standard or competing format. Could vary if the library is particularly large or end format proprietary.
That way people who hate subscriptions or lock-in know they have an out and don’t have to lose anything.
