Systemd is too much, but often busybox is not enough. Plus if everything starts conforming to systemd, busybox will have to become like systemd to stay compatible.
It's not just GNOME; an embedded device that acts as a USB host needs something like udev, and as I recall reading systemd has swallowed the hardware plugging notification systems, or was working on it. The success of systemd in getting single-user kernel patches that only make sense for desktops and systemd is most concerning, though. Linux is great because of its modularity; previously, if init didn't make sense you could switch to openrc, upstart, or others, without having to change the way you do logging, DHCP, hardware plug events, etc.