In situations such as Las Vegas, no amount of concealed or open carried firearms would have made much difference. A rapidly fired weapon from a higher vantage point with a clear view of the crowd has a clear advantage over 600+ people firing blindly at a casino/hotel.
That said, I am not opposed to firearms, but I would like for their to be some mandated training and maybe stricter background checks. I don't know that these will do anything to stop angry people from doing terrible things, or if we even CAN stop that, so I guess I am among those who just want SOMETHING to be done. I generally keep my thoughts to myself on this, though, as I don't see it being helpful, just adding to the noise.