[javis]

Doesn't the requirement that the client not be behind NAT render this somewhat useless?

Isn't the vast majority of the internet behind NAT?

[psionski]

Two words: port forwarding :) Yes, it makes using TOR a bit more difficult, but not by very much...

[coopdog]

Plus IPv6 could drastically reduce the need for NAT (particularly in mobile where they're basically out of IPs and basically NAT the entire mobile network)