FMI is pushing FLT and Web Direct. It is a big move to support 5 WD worker machines and 500 users. Each of these needs SSL and a FQDN for each server. This requires a DNS Server on the LAN.
It would be a nice full package if there was a simple DNS panel in FMS admin console for managing the workers and providing A records for "www" and "ftp" to leave the local network. This would be super nice as it would be all managed in the admin console and no need for an additional server. A DNS server is generally a light load and with WebDirect the Master generally will not see much load at all in most cases.
I have run macOS Server on the same machine as FMS for DNS and it works just fine. Setting up DNS services in macOS Server is pretty easy and Windows is not too bad either, but there is not a lot of info on it and for many it might be difficult to figure how it works the first (and likely only) time they set it up. It can easily interfere with the Admin console and local WD connections even when the Web service are off. Having an built in DNS service in FMS would be great.