Smaller bezel would be nice. 5" screen would fit the current frame and the top/bottom bezel would be alot smaller.
And 1 thing I'd really love is FM radio...from my experience, it uses ALOT less battery than internet radios.
possibly better camera, not too important for me tho.
720p screen. I think 1080p is just too power-hungry.
and ofcourse bigger battery, but only if its possible without increasing the thickness...(I kinda fell in love with thin phones :P)

there r other things too like memory and processor but I'm not gonna go there this time.