Well, first off, I want something revolutionary that I'd never thought of, like the sharing music stuff, etc.
But, of the things I don't need apple's genius to invent-
Better radio support. Maybe it's just that real and wma have the formats, and it's not apple I need to complain to, but internet audio sucks, itunes wise, and the mixing/seperation of radio and songs is messy. maybe they could pull a harmony move right back at real?
Second, I'd like something to tell me the quality of the song. No, not just bitrate. I'd like some kind of overall score-i've got lots of songs from scratched cd's, bad recordings, low bitrate, etc. and I'd like to replace them, without all the effort of listeing and keeping track of which are bad. Also, I'm disorganized, and when I do replace them, or otherwise get multiple copies of a song, I'd like to be able to throw away the bad one, and keep the good. But currently, that's a bit hard.
I'd like a cleaner itms interface, and as big a catalog as they can possibly get. Particularly, it would be AWESOME if you could have it integrated with radio playback, so it would try and identify the song you were listening to on the radio (either from the radiostation or just powerful software), and show it to you to buy/the album it's in.
One more itms thing-suggestions should be based not on what is currently in your shopping cart, but everything you've bought. C'mon apple, that's such a good way to get people to buy more....