The point about NAT blocking unforwarded servers, not necessarily true: http://samy.pl/pwnat/
The goal of some botnets is to set up servers for software distribution or to host phishing sites. You can't characterize botnets activity as simply client behavior.
Thanks to UPnP being enabled on most modern consumer routers you can't even count on the NAT protecting you from having a unauthorized server.
Having end-devices NOT be servers is ignoring the fact that the UI for many home devices is delivered over a embedded web server. This is becoming more commonplace over time.
Ultimately you need a firewall that controls inbound and outbound traffic.
The goal of some botnets is to set up servers for software distribution or to host phishing sites. You can't characterize botnets activity as simply client behavior.
Thanks to UPnP being enabled on most modern consumer routers you can't even count on the NAT protecting you from having a unauthorized server.
Having end-devices NOT be servers is ignoring the fact that the UI for many home devices is delivered over a embedded web server. This is becoming more commonplace over time.
Ultimately you need a firewall that controls inbound and outbound traffic.