Yes, reverse geocoding has improved. Now you can get the latitude and longitude values of any location object created with the findresults or find addressresults method. But this is a one way. Of course you still can't get the streetadress of a location object created with the getlocation method.

I can't see major changes in the control, but it seems that any application created with the MapPointControl 13 (2006) is incompatible to the old Control (2004).