Telnet is still incredibly useful as a troubleshooting tool, but I'm not surprised that MS is just dumping it completely.
It's good to hear that MS will finally be joining the rest of the world in supporting ssh. I'm sometimes astounded at how long it takes microsoft to make sensible moves like that. I haven't used telnet for anything other than a network connectivity troubleshooting tool for years. Anyone still running telnet servers except in really specialized circumstances should have been shot years ago.
As a tool: The telnet client yes, but not the server that has been the only option for years on MS for low bandwidth connections. Telnet is about the best first line tool there is for trouble shooting smtp problems.