I did some work with hub motors a while back. The unsprung mass is still under debate, but moving all that mass to the corners of the vehicle is actually a good thing. I would think putting the inverter in the hub would make for terrible durability problems, but who knows.
Anecdote: The hub motors I wrote code for had integrated planetary gear, so they ran 6000rpm at the motor. The rotor was on a rather large bearing and we had all sorts of runout and alignment issues. It's was really hard to package in that space. We had peak power of 40KW per wheel, but you only got that for about 30 seconds before needing to cool off for 5 minutes (it was also water cooled, but not well - packaging again). Because of the heating and alignment issues, nobody could make much progress on doing the software calibration (motor mapping) on it. It was the only motor we had that required my new algorithm to get it up and running. It made light work of the calibration, compensated for the alignment and eccentricity issues, and ran the hell out of that thing. Sometimes I miss working on that stuff ;-)