If your needs are simple, the resulting unit file is trivial and you can basically copy and paste from any example without looking at any documentation.
If your needs are complex, you have better chance by mixing different options in the completely declarative syntax of systemd than mixing shell snippets from different scripts using different styles.
In any case systemd happily launches LSB-compatible init scripts, you literally don't lose anything.
> Complex needs are better solved with source code rather than special blobs of $system.
Arguably, reinventing multiple complex wheels is often a not particularly good choice.
So either you're implementing something really novel in your init script (which does not sound like the best place for it) or it's something that may benefit from a single, shared and tested implementation.
And, again, you can still fallback to LSB shell scripts if you really need something incredibly special: my point was that, bloat notwithstanding, you don't lose any feature but gain many.
If your needs are complex, you have better chance by mixing different options in the completely declarative syntax of systemd than mixing shell snippets from different scripts using different styles.
In any case systemd happily launches LSB-compatible init scripts, you literally don't lose anything.