It could be very useful, when Amarok could sort my files in my "Music library" (directory with all music), like Banshee or iTunes.

So, it will automatically creates/change structure of folders on disk to somethink like [Artist]/[Album]/[Number]-[Song_Name]

So it can reorganize my messy library in filesystem. It also automaticaly adds imported music to dhis "Media library" folder, using same rules.

Do you plan this feature in some next version?

You didn't state what Amarok version you are using, but Amarok 2.3.x has the Organize Files option (right click in the Collection Browser). Please make sure you have a backup before moving files around, though.