Does this mean we ban all filtering of traffic on the public Internet, imposing the end-to-end rule in earnest, leaving all security to the end hosts? This does seem to be the flavor of the original IPv6 discussions around stateful packet filters. This does not, however, seem like the most realistic option available; the stronger defense is not a single perfect wall, but rather a series of less than perfect walls. Defense in depth will beat a single firewall every time. Another alternative is to accept another bit of reality we often forget in the network engineering world: abstractions leak. The end-to-end principle describes a perfectly abstracted system capable of carrying traffic from one host to another, and a perfectly abstracted set of hosts between which traffic is being carried.
The full post can be read over at the ECI blog.