I was thinking the same thing. I'm definitely looking forward to hearing something a bit more well refined and orchestrated seeing as we're moving to a better system, but I wouldn't object to an item like the GB Sounds making a comeback. Even though the GB Sounds main purpose was for nostalgic sake, I wouldn't mind hearing what the newer tracks turned into 8-bit tunes would sound like while playing....that said, a GB Sounds item that converted it all to 8-bit would be well received by me.
As for the new music in general, anything that wasn't like Black and White or Black 2 and White 2 (Sorry, Nica!). Now this is all up to personal preference, but I personally found a lot of the music in Gen V to be far too cheery and not played up or dramatic enough for certain locations or battles. Listening to the Black 2 and White 2 Champion track right now, it just doesn't feel like the sort of music you'd hear in a Champion battle. With the exception of the final battle with N and Ghetsis, the Gen V music could have been better in my opinion.
The one thing I did like about the Gen V, was that they brought in lyrics. I hope we can hear that again with the 3DS sound, but with a more widespread use of words.