As a Devuan user (not a dev), it's more than just the init system though. Devuan is also doing lots of heavy lifting to keep udev separate from systemd, as well as other things (consolekit and polkit come to mind, as does dbus).

At this point systemd is a whole lot more than an init system. Most people don't have a complaint with regards to systemd units or how fast it boots, it's more to do with the amount of dependencies it seems to be sucking in (at least from my experience).