I agree with Chen on the buttons. In fact, I wish someone would revive Nintendo's simple and elegant SNES solution to telling buttons apart: make some rounded ones and some bowl-shaped ones. After an hour or two of playing I never had to look at my Super NES controller again to figure out which button to press. Every time I play an Xbox or a PS2, I spend half of my time looking down to figure out what I need to push. I'm sure I'd get used to them eventually if I owned one of those systems, but I've played both quite a bit with friends, I shouldn't still have to look down all the time.
Stereo speakers are a little pointless on this system, but I don't think they'll do any harm. Maybe some developers will overdo the stereo, but I don't think it will be an issue for most games. And they do make it look fancier.
Definitely an improvement, but honestly, I don't care, I would have played it in any form.