Why?
What is the appeal of writing immensely long, fragile shell scripts?
Having to wrap them in various monitoring and logging daemons
Having to have different ones for every distro you want to support with your software
Is this something that is truly a productive use of your time? Putting aside the question of if systemd is "good" or not. Is the current sysvinit system truly "good enough" and not in need of change?
Something having been used for decades certainly doesn't mean that it's optimal and shouldn't be changed, but it does strongly suggest that it's good enough.
For me it's relative and a case of "the devil I know". I actually prefer BSD-style init to sysvinit, but I've used the latter for ~20 years. I'm aware that traditional init systems may not meet the requirements of certain users (eg. those who run very large server installations), but for my simple use case (small servers and workstations) they do the job.
I'm not against change per se; I'm running Void (with runit) on one of my systems, and the desktop I'm using to post this runs OpenBSD.