I was wondering the same thing. I don't want to save my dad's address as 4554 Mockingbird etc... I want to save it as "Dad". Seems pretty stupid this way.
Even if you go to googlemaps on your PC, you can't change the favorite name.
Oh, and let me know if anyone figures out an easy way to transfer bookmarks from Applemaps to Googlemaps (besides copy/pasting one at a time).