of course it is, 20 years ago if you had internet, you most definitely were not behind NAT. now, you most likely are. upnp is a prothesis that should die ASAP.

Even though I agree that UPnP is a solution for a problem that shouldn't exist in the first place, I wonder how secure that kind of P2P communication will be. I guess people will still need/want residential firewalls and automatic ways to bypass them.