Unit Tests Skipped
I don't personally use the system ftpd myself (used pureftpd for all my previous systems, and no longer running ftp service for a decade now), but I think it is a relatively simple (even compared to pureftpd) application to demonstrate PAM, sendfile, how to write a service daemon, etc.
That's said, I'm neutral with the deprecation but would expect some objections from the community.
I think we should deprecate the client as well. F5 no longer supports the FTP protocol.
Another thought: Deprecate and remove telnet. It's already in contrib and could be very easily moved to ports. (I'll put that on my todo list.)