"best" meaning the best decision the LFS team can make given their limited, unpaid time and resources. They feel maintaining guides for two parallel init systems is unsustainable even though they would prefer not to have systemd as the only option.

The actual best decision would be to stick with his principles and make LFS be sysvinit-only instead, with zero fucks given about Gnome/KDE if they refuse to play ball.

I for one will not be strong armed into systemd or any other tech. If KDE makes it impossible for me to run without systemd, it goes into the trash bin. I will just install Trinity (KDE3) and be done with it. (Gnome deserves no consideration whatsoever.)