Comentário oficial
1) Already been suggested.
2) Already in progress.
3) Sorry, this isn't iTunes.
4) Already in the preferences under View, uncheck this box:

5) Consider using the INFO panel on the right:

6) You can't "sync" to folders, you need to import the music to rekordbox. There is no way to automatically add/analyse folders on your drive, nor is this a good idea for technical reasons.
7) Serato doesn't export for use with other applications. Traktor doesn't export for use with other applications. rekordbox CAN export an XML file already!

8) That tag is exclusively for use within rekordbox as it's not a standardized tag across MP3s or metadata fields on other filetypes.
9) Already exists - select any track then click the little triangle to show the info.

10) Users already complain about the speed of export, that sounds like a reason for users to complain even more, not cheer for a beneficial feature.