''As a personal note, I do not like this decision. To me LFS is about learning how a system works. Understanding the boot process is a big part of that. systemd is about 1678 "C" files plus many data files. System V is "22" C files plus about 50 short bash scripts and data files. Yes, systemd provides a lot of capabilities, but we will be losing some things I consider important.
However, the decision needs to be made.''
Going systemd-only is not necessarily a good choice (though I do understand it from a practical point of view). There are other, better alternatives for System V that are smaller and more modular so you still get the Unix "feel" without the absurd complexity of interlinked shell scripts that System V relies on.
I'd like to see OpenRC getting adopted in System V's place. Upstart seems to be dead (outside of ChromeOS) but it would also have sufficed. Alas, I'm not someone with the time or knowledge to maintain these tools for LFS, and unless someone else steps up to do all the hard work, we'll probably see LFS go systemd-only.
That said, there's no reason to go full-fat systemd, of course.
The reason it is being removed is precisely because now we are in the Linux era, no longer in the Unix era.
Have another vote in favour of OpenRC, and even Upstart, if it somehow revives.