Maybe, just maybe a few of these things will tip the scales this time:
1) Event was capured in realtime with many phone cams --- you can hear the automatic gunfire plain as day, and it no rational person could justify that rate of fire being available for anyone outside of a warzone
2) The shooter is just an average Joe, no criminal history, not even any mental issues, not a vet (from what the family says), no military training, nothing. The only shred is an unconfirmed link to ISIS which may (likely) be BS.
Sandy Hook shooter had a crazed look in his eye and was clearly mentally unstable. This blows the doors off of the "mentally challenged people shouldn't have guns" part of the discussion. Maybe, just maybe the populace at large will come together and agree that if an average Joe with no criminal history can just snap and do something like this with these sort of warzone-only-applicable weapons, then there needs to be some serious reforms and restrictions on weapons available on the market in this country and severe penalties for modifying said weapons in ways like this shooter likely did....