I think this post convincingly argues that there exists a world (but not ours, due to path dependence) where IPv6 is a better design: https://apenwarr.ca/log/20170810
Not really, it just spends a lot of time waffling on about bus networks and mobile IPs and then makes some weird claims about the IETF that don't seem to match reality.
v6 is designed the way it is precisely because it needs to run on the same networks that v4 does, and v6 is a better design than v4 in our world because our world has completely outgrown v4.
