Yes, and if your host has access to several IPv6 addresses and maybe an IPv4 address it'd be nice to have something like wireguard actually utilize all of them in some random order. Same on the receiving end, wireguard server listenes both on IPv4 and IPv6 at same time and internally puts received packets in the proper order.

I feel this would create significant struggles for any surveillance software because most firewalls I know are modeled on a source address / target address basis.

If you have access to enough source IPv6 addresses you might even put your whole wireguard traffic into ICMP packet payload?