Hi jh0nny, I do have plans to add extended music support for the premium version (full soundtracks, etc.). And scrapers for the music and manuals, etc. are planned as well.
I see where you're going with editing the sidebar, but at some point it does get too complicated, and I've always wanted to focus on simplicity and ease of use. That said, I do still plan on adding an option to hide the (Exists) and (None) items.