I've replaced telnet mostly with netcat e.g nc -v <host> <port> as a quick way to see if a host is listening on a port. It's probably not as informative as the s_client but I can see where s_client certainly would be more useful for troubleshooting an encrypted connection. Thanks for reminding me about it!
I don't overly care about which init system is running as long as they work and for the most part systemd has just worked for me, maybe I'm just lucky. As far as creating new unit files and such, yeah, there is a learning curve compared to just throwing together a bash script, but for some people they both involve the same level of arcane magic. Fortunately, I haven't had to create many from scratch and when I've gotten them squared away they seem to just work. Does systemd still have issues and is it getting into everything? Sure, but like Seth pointed out, at least the interface to it is relative consistent and some feature can simply be turned off and an alternative used. I find it more productive to adapt and learn as much about the systems I admin than whine about change (even if it's perceived as change for changes sake). Just my $.02