I think it's an outstanding compromise. He's not demanding that everyone give up every firearm they own, but saying "look, these assault rifles and 20+ round magazines are absolutely ridiculous." There's absolutely no reason for civilians to possess that kind of firepower. So I applaud Obama's administration for putting this out there and I hope it gets traction.
In a majority of the cases, the weapons used in shootings were purchased legally, so taking assault weapons and large capacity magazines off of the table will have a larger impact than we imagine.
Now, I know the age-old retort that those same shooters would have purchased their guns illegally. Well, I wonder if that's actually true. For one, I think finding someone who would deal black market firearms is harder than it's depicted in the media. Another thing is that the person purchasing the firearm has no idea if the dealer's being watched by any law enforcement agencies or if the weapon itself is "hot", so all of those variables could actually be a deterrent.