As for Linux from Scratch - This is something that's been on my radar, but without the part I'm truly interested in (learning more about SysV) then I'm less inclined to bother. I don't buy the reason of Gnome/KDE - isn't LfS all about the basics of the distro than building a fully fledged system? If it's the foundation for the other courses, but it still feels weak that it's so guided by a future GUI requirement for systemd when it's talking about building web servers and the like in a 500Mb or less as the motivation.
All the compliants I see tend to be philisophical criticism of systemd being "not unixy" or "monolithic".
But there's a reason it's being adopted: it does it's job well. It's a pleasure being able to manage timers, socket activations, sandboxing, and resource slices, all of which suck to configure on script based init systems.
People complain in website comment sections how "bloated" systemd is, while typing into reddit webpage that loads megabytes of JS crap.
Meanwhile a default systemd build with libraries is about 1.8MB. That's peanuts.
Systemd is leaps and bounds in front of other init systems, with robust tooling and documentation, and despite misconceptions it actually quite modular, with almost all features gated with options. It gives a consistent interface for linux across distributions, and provides a familar predictible tools for administators.