The biggest advantage is that repealing registration turns a privilege (asking govt permission to purchase a handgun) into a right (no govt permission to purchase handgun). The rest is a non-argument. It's like saying that if you get a government permit, they'll allow you to talk freely outside of your house.
I agree with you on rifles/shotguns. Although I don't have any type of clothing where I could possibly conceal either. It would be nice if they would get rid of the transport laws for rifles/shotguns. Colorado, while not perfect, is pretty damn close, in that a rifle/shotgun can be carried anywhere in a vehicle, uncased, with a loaded tube/magazine/clip inserted (where applicable) as long as there isn't a round in the chamber.