I know there is not much space in helmets for speakers (so they must be relatively small), but a bit more base would be very nice for sound quality.
A bit more volume would also be nice. I have a goldwing for which wind noise is not a problem. The volume is okay. However, I also have a sport bike for which wind noise is much worse, so I typically wear foam ear plugs to protect my hearing. The problem is the wind noise on the sport bike completely drowns out the speakers. If there was more volume from the speakers, I could hear the music above the wind noise even with ear plugs (i.e. better S/N ratio with ear plug attenuation). I'm pretty certain this is possible since the firmware 4.0 voice that announces "hello" and "good-bye" is louder than my music.