Embedded? Ancient? What sort of systems are you telnetting into?

Not the parent poster, but I also still use telnet. For me it's "Ancient", I have a few retired SPARC and PA-RISC boxes that run their period appropriate OSes as a hobby. Telnet/rlogin is the more reliable method to get into them remotely (just over the LAN).

They're on a LAN behind a NAT Router/Firewall, and I don't always keep them powered up (I'm not that insane) so I really don't have a concern for them.

Some of the more modern/high-performance examples I have run NetBSD with modern sshd and modern ciphers, but you can tell it's a bit of a workout for them.