I have three wishes for you.
1. Advanced genre management:
I think, many users have multiple genres for a song. E.g. in my archive, a soundtrack has everytime the "soundtrack" genre. But then I differentiate between soundtrack compilations of different artists (marked additionally as "compilation") and composer music marked as "score".
Would it be possible to check / uncheck a special genre when multiple files with multiple genres are selected? Or did I miss a script that's able to do this?
2. Advanced custom tag management:
Like genre tags I would like the ability to have custom tag sets to use. For example this could be tags like "live, single, guitar, piano, synthi, digital, warm, cold, aggressive". Yes, I could do this already with the genre tag but then, I would mix up the original intention of it with any special tags.
3. Related artists:
And the third wish is to link different artists. Maybe I would link Mozart & Beethoven, or James Newton-Howard and Christopher Young, because there music has in my mind some relations. Then I could create playlists which base on these relations. I know this is already possible with last.fm integration but a native and network independent solution would also be good. Another point is that you can make your own relations between artists.
I hope, some of my wishes are a bit interesting.

Regards,
Christoph