My only input into the matter is that if you NEED ipv6 implemented into pfSense that you submit a proposal to the developers through their corporate support for development services. They have stated before that from a hobbyist development point of view, they do not have access to ipv6 systems to warrant them to do it in the near future but would work on it if there was an official paid development effort.
In the mean time, pf as a service can run ipv6 and can run dual stacked with ipv4 for those that need it. https://solarflux.org/pf/pf+IPv6.php in summary, unless someone pays for it or adds it themselves, it wont be added anytime soon. -Sean
