Even people I have spoken that understand the difference between firewalling/reachability and NATing are still in favour of NAT. The argument basically goes "Yes, I understand that have a public address does not neccessarily mean being publically reachable. But having a private address means that [inbound] public reachability is simply not possible without explicit configuration to enable it". i.e. NAT is seen as a extra layer of security.
I want NAT to die but I think it won't. Far too many "security" folks are dictating actual implementation details and that's fundamentally wrong.
A security policy should read "no external access to the network" and it should be up to the network/firewall folks to determine how best to make that happen. Unfortunately many security policies go so far as to explicitly require NAT. -Don