I don't know how to write sysvinit scripts any more than I know how to write fizzbuzz. What I do know is how to program and specifically how to write and maintain and debug shell scripts. I NEED that for other automation purposes and cannot get rid of that mandatory requirement so it used to dovetail quite well with init scripts. There are corner cases and security issues and tradition, which means copying a known good init script and editing nothing but the executable names is a great start, but its not really a serious problem. I don't care if its verbose, as long as its simple and understandable and most importantly, predictable.
Now instead of applying a language and tradition I know to a simple task like init, I get to learn a whole new ecosystem and technology to do about the same thing I always did except vastly more complicated, and I can't even shed the old knowledge because its needed elsewhere. That makes overall systems harder to use, slower, buggier, and less reliable. And thats defined as "progress" because its new so it must be better.