alt Hacker NewsAn explicit goal of IPv6 considered as important as the address expansion was the simplification of the packet header, by having fewer fields and which are correctly aligned, not like in the IPv4 header, in order to enable faster hardware routing.
The scheme described by you fails to achieve this goal.
I am glad you brought this up, that is another big issue with IPv6. A lot of the problems it was trying to solve literally don't exist anymore.
Header processing and alignment were an issue in the 90s when routers repurposed generic components. Now we have modern custom ASICs that can handle IPv4 inside of a GRE tunnel on a VLAN over MPLS at line rate. I have switches in my house that do 780 Gbps.