The funny part is that if the top level peers said on date X we will only route IPv6 packets and the top level DNS root servers said on date X we will only respond to IPv6 queries, the net result would be an increase in job opportunities for small to mid level tech service companies. Sure, many ISP's would have to work to handle the change as well but in general I see it as an win / win. Perhaps if the government was serious about all this they would even throw monies to the states to cover the increased associated IT costs to get state services compliant. There are many positives that would come out of an IPv6 mandate.

Having been intimately involved with spammers over the years I can say that this change will only escalate the ongoing game of use / burn / blacklist / move on. Yes, more poor commercial entities will unknowingly and unwillingly have to call in Wally the IT guy to help them get off some blacklist somewhere so their mail will flow, but in the grand scheme this will not change the processing power of the mail bots or tilt the scales in a significant manor. IMHO.