You've made one of the most compelling points I've seen in this discussion so far. Really - why mix an application security mechanism into the transport layer?

You've made one of the most compelling points I've seen in this discussion so far. Really - why mix an application security mechanism into the transport layer? DDoS attacks will happen whether Tor is blocked or not. Add to this some other interesting points I've read here regarding: IPv4 exhaustion, NAT and IPv6 growth. All signs seem to point to the need for an application level solution.