Keeping them safely secure makes them obsolete for defense. No criminal is going to wait while you run upstairs unlock the gun safe, recover the weapon, and load it.
I don't have a problem licensing them for particular activities(police, security guards, fbi, private investigators, bounty hunters, hunting(because you need the food, not for sport), target practice at a licensed range, etc). I might not even have a problem with it if you had to be a member of an organized and regulated militia.
Anyone I encounter on the street with a gun is going to be treated like an outlaw(by me anyway). I don't have a problem with the outlaws having guns, that'll make it easier to arrest them as you won't have to wait for them to do anything else, you can just arrest them for possession of a firearm.
The only valid self defense argument I see is for like Alaska or something where you might exit your house only to find a bear attacking you or something like that.