I think wireless tether and perhaps underclocking the CPU when not needed would be the best reasons to root..
I really hope we can find a way to run custom ROMS.. all I really want is vanilla Android.
*Opinion*
Dear Moto: If you're reading this (you clearly aren't), please just give us vanilla Android... the majority of us would prefer it over your MotoBlur crap. It saves you time/money, and makes most end-users happier.
Note: I know it's not "technically" running MotoBlur... but it might as well be. Same, ugly, unintuitive interface.