They did solve one more problem that leads to performance boost. IPv4 header contains checksum field which must be recalculated on each network hop, as the add

They did solve one more problem that leads to performance boost. IPv4 header contains checksum field which must be recalculated on each network hop, as the addresses change with each one. Other than that? i agree. IPv6 is an disaster, and it wouldn't be so if we moved early - but there were no incentives at all to move early.