Re: IPv6 was designed by theorists
Who cares about being "checksum neutral", what a stupid reason to design something that's user unfriendly! Computers work for us, not the other way around!
Two extra octets gives you 65535x bigger address space. The v4 hosts don't need to contact all the "extended address" hosts, they would be in their own world, and a dual homed interface (like how IPv6 works now) would let them communicate with the outside world using the new 6 octet scheme.