I agree that the usb is faster... I still don't see why it's not an option though. I would hate it if they changed it to ONLY wireless syncing, but I don't see why they wouldn't add it as an option. With the phone (and I suppose the touch), I love that my contacts, calendars, etc are all wirelessly sync'd through .mac just because of the convenience of knowing I don't have to keep my iPhone by computer if I want to change someone's phone number.
Depending on the person, other than the first sync, not a lot changes (for me at least, maybe an album or two at a time) but I would love to be able to leave my iPod by my keys, go to my computer, hit sync and then just leave it.