I have yet to see a "NAT is not security" rebuttal that does not make either one or both of these points:

- NAT is not a security feature because it wasn't designed as one (this post), and/or

- NAT is not a security feature because it does not, without a firewall, protect against an attacker on the WAN subnet, or another difficult-to-exploit scenario.

And yet making LAN devices unroutable from the Internet does on its own makes exploitation much more difficult. It's admittedly not a perfect measure, but it's one that IPv6 deployments with routable addresses for LAN devices lack. I would wager this does make a difference in the proliferation of botnets, especially given the lackluster standards of consumer network equipment security.