IPv6 is the reason why we can't have IPv6
Your IPv8 is what IPv6 should have been. Instead, IPv6 decided to re-invent way too much, and is why we can't have nice things are are stuck with IPv4 and NAT. Just doubling the address width would have given us 90% of the benefit of V6 with far less complexity and would have been adopted much, much, much faster.
I just ported some (BSD) kernel code from V4 to V6. If the address width was just twice as big, and not 4x as big, a lot of the fugly stuff you have to deal with in C would never have happened. A sockaddr could have been expanded by 2 bytes to handle V6. There would not be all these oddball casts between V4/V6, and entirely different IP packet handling routines because of data size differences and differences in stuff like route and mac address lookup.
Another pet peeve of mine from my days working on hardware is IPv6 extension headers. There is no limit in the protocol to how many extension headers a packet can have. This makes verifying ASICS hard, and leads to very poor support for them. I remember when we were implementing them and we had a nice way to do it, we looked at what our competitors did. We found most of them just disabled any advanced features when more than 1 extension header was present.