So Skype has a 100% success rate piercing NATs and does not require any fallbacks?
Also you mentioned that you do not use STUN/TURN, what other solutions are there that allow for p2p data streams between browsers?
Yeah IPv6 is valuable but it seems NAT is the smallest inconvenience since a p2p connection can usually still be made. Briefly giving it thought, I don't think IPv6 could rid the use of TURN servers or close the other 5% of anomalies. Am I wrong?