Maybe I'm just getting old and change is starting to grate on me. But systemd does feel like everything-and-the-kitchen-sink.
As for SELinux, sure, you can turn it off. At which point it's useless. The pain begins when you actually want to use it and existing policies aren't enough. It is hugely complex. Tooling (like ausearch and audit2allow) is, erhm, not very good. Want to allow something non standard? Better be prepared to spend a couple of hours. Don't forget to turn your new policy into a module file. And then compile that into a pp file, which is another kind of module? And then don't forget to install that file. I remember administering Windows NT and 2K boxen and really hating how its policies worked, well, SELinux now makes me feel the same.
Both of these tools make a lot assumptions about how things should be done, and they're pushing these assumptions onto the user, whether or not they agree.
And hey, I get it, these are complex domains, and we should be very happy that people are giving us Free (both sense) Software in the first place. But boy, if I could pay €100 to have a sensible operating system, I would. Just not €100 per machine -_-