No we wouldn't, I worked on routers in 1997: the differences with IPv6 made our job much easier. The hard parts about IPv6 are changing the number of bits makes everything incompatible. That means all software and books needs to be rewritten to work with the new protocol and there is no way around that.

Of course you probably never worked with source routing in IPv4 - I spent a lot of time testing it because marketing couldn't prove none of our customers used it. Even then nearly all routers shipped configured to drop any packet with source address routing, but to comply with the rfcs we had to make it work.