Suggestion about Multi-WAN algorithm
I suggest to refactor multiwan algorithm from round-robin to hash select.
For example, router can take last bits of IP address and determine by them, which gateway to use.
This will guarantee, that single site will be accessed via single provider, which is important to some session-secured sites, like online banks.
IIRC that's a limitation of pf. It can't use anything other than round-robin or round-robin+sticky when specifying multiple addresses in that way. To use hashing it would have to use a network in that context, which doesn't make sense for gateways. If you want to see something like that, you'll have to advocate to pf directly (OpenBSD) or perhaps FreeBSD since the pf in FreeBSD has diverged from that of OpenBSD.