That's only a "good plan" if you agree that less guns is a good thing. For someone who considers weapon legislation as "light" as Canada's to be an abomination and a crime against humanity, they will look at that sort of plan and see exactly what it is, a prelude to much greater weapon restrictions, particularly any form of "voluntary" registration*.
Of course, that also runs aground on the hard fact that you'ld be forcing something on the electorate has repeatedly and loudly stated they DO NOT WANT.Despite some popular claims, the gun control movement has NEVER had the support of a majority of the population for longer than a month or two, and even in those cases the support extended only to very, very limited measures.
*Many programs (the 55 MPH speed limit, 21+ drinking age, and several other laws past and present that are universal despite being state laws rather than federal) have already been forced through by the government through "voluntary incentives" that were either so lucrative that local governments simply had to comply, or were quite literally an "offer you can't refuse", in that refusing would be economic suicide. It would be extremely easy to craft a registration program of that sort, where access to gun ranges, ammunition, or new guns is prohibitively expensive or effectively impossible without "Volunteering" to go on the registry. MOst people view a comprehensive registry not simply a long step toward confiscation, but practically confiscation's roommate.