So what I had thought was an issue with the interfaces on my pfsense box was actually just an issue with the wifi access point / switch only supporting 100Mb connections. I clearly need to get something newer. Fortunately that means I'll never have to touch the pfsense box again until it someday dies, but does mean that I need to switch out my wifi access point with a better one.
Right now the TL-WA3001 is catching my eye, but I am very open to suggestions if anyone has better ideas. I do want an access point that I can just set on a table and let run rather than a device that I'd be expected to mount to a wall or ceiling, even if that cuts out some of its effective range. Where it is right now is actually a pretty central spot in the house, and there aren't generally connectivity issues.
This kind of commitment to finding things out through repeated fuckups is the nine-sixes tech difference.