> Besides the difficulty of that by itself, it automatically meant that the v6 versions of DNS, DHCP, NAT, etc wouldn't support v4, rather it'd be a totally separate stack.
Sure, "make the addresses bigger" would have required providing DHCPv6, DNS AAAA records, and various other protocol updates for protocols that embedded IP addresses. And making changes to the protocol header at the same time (e.g. removing the redundant checksum) were also a good idea.
It didn't require pushing SLAAC instead of DHCP.
It didn't require recommending (though fortunately not requiring) IPsec for all IPv6 stacks.
It didn't require changing the address syntax to use colons, causing pain for all protocols that used `IP:port` or similar.
It didn't require mandating link-local addresses for every interface.
It didn't require adding a mandatory address-collision-detection mechanism.
Sure, "make the addresses bigger" would have required providing DHCPv6, DNS AAAA records, and various other protocol updates for protocols that embedded IP addresses. And making changes to the protocol header at the same time (e.g. removing the redundant checksum) were also a good idea.
It didn't require pushing SLAAC instead of DHCP.
It didn't require recommending (though fortunately not requiring) IPsec for all IPv6 stacks.
It didn't require changing the address syntax to use colons, causing pain for all protocols that used `IP:port` or similar.
It didn't require mandating link-local addresses for every interface.
It didn't require adding a mandatory address-collision-detection mechanism.
And I'm sure I'm forgetting a few.