I don't think most law-abiding gun owners will care if bump stocks get banned. A bump stock is a modification that, while legally in compliance, does skirt around the spirit and intent of the 1986 NFA legislation. I think at least considering NFA regulation (similar to how suppressors and full auto's are regulated) would make sense.
That said, any restrictive legislation or even an outright ban would be mostly a symbolic, feel-good gesture that would have little practical affect on would-be attackers.
Firstly, in the age of 3d printers, we're not too far away from a world where people can manufacture these devices in their living rooms. Heck, we're not that far away from a world where people can manufacture entirely untraceable firearms in their living room. A ban or restriction would inhibit law-abiding citizens, but would do little to nothing to hinder evil people with evil intentions.
Secondly, mass attacks have been consistently carried out in many European countries (most of which have far more rigorous gun regulations). Attackers have used bombs, vehicles, and even the much vilified semi-auto rifles to cause similar, or some cases worse, carnage compared to what we saw in Las Vegas. Despite what late-night comedy hosts and politicians claim, there isn't some magic, panacea piece of legislation that is going to stop future attacks from happening.
Thirdly, there are lot of misconceptions about full auto fire, whether it via a true automatic weapon or simulated via a bump stock. It can inflict a lot of death in certain situations (e.g. shooting into a tightly packed crowd from an elevated position). However, in most applications it isn't as accurate as taking single, well-aimed shots. All of the grunts and spec ops fellows have full auto, or at least 3 round burst, capabilities on their M4's and M16's; most of the time they're using semi-auto mode because it is inherently more accurate than the automatic mode. Full auto fire is very hard to control and manage, especially without the use of a stabilizing bipod or tripod and a T/E. Anyone who thinks otherwise has relied on Hollywood movies and fantasy to form his/her opinions.