It should be clarified that Devuan is NOT without systemd. It is used in udev, and its intended replacement, vdev, has not been updated in around a year:https://github.com/jcnelson/vdev
(Possibly not a priority for a community that is largely sysadmin based - who needs to spin down a server!!!).
eudev is being actively maintained at:https://github.com/gentoo/eudev
but I do not know how seamlessly a gentoo util would fit into a debian system (thinking directory organization).
The only difficulties this systemd/udev seems to have caused here is the breakage of basic power management, like hibernation. Not as issue as the functions can be replaced by other software. In fairness, this is a large install, so it may be possible that the power problems are caused by other conflicts.
It needs to be stated, and even endlessly repeated that systemd is *not* the devil. It is metastasizing corporate software hiding behind GPL3 cover.
As a system lib it is harmless, even possibly benign. But it is as an ever expanding *process*, with aspirations of even taking on kernel processes (and it has already caused Torwalds problems) - is wherein the issue lies.
In my Win boot I have no problems using Ubuntu/systemd as a VM. Its not meant to be a base or productive system. I dont intend to run servers on it. I dont even reallly intend to customize it. Its an *appliance* there. Like a can opener. And as a can opener it runs fine.
Now, *this* system is being packed to the gills. My long terms plans are simple: As Debian veers away from traditional Linux, i will veer away from it. All updates are turned off, the Devuan ops can all take a hike to Shangri-La, but my future plans are to hack the dpkg/apt system here, and do my own .deb filtering.
As far as reversion back to 'pure' debian goes, I do not believe it would be difficult. Just remove devuan from sources.list, go to synaptic, enter 'devuan' in the search function to take a look at exactly the devuan packages installed ( i see 94 TOTAL packages, mostly i18n, with only 18 actually installed.). apt-get update;apt-get-upgrade, and possibly even apt-get dist-upgrade should so it. I would consider removing non-essential packages first. And of course, backup (to an ext filesystem, and not NTFS or a default format USB stick!)
Hopefully there is a Devuan 'undo' FAQ around somewhere. If not there needs to be one.
The arguments over systemd inevitably reflect a clash of cultures. And a concept of what an OS is, and what it means. For some of us, a well tuned OS is as certainly as dear as a fine tuned musical instrument. Imagine a musician replacing parts of his piano, only to find his keys no longer are hammers to anything, but are now optical switches. And the innards have been replaced by a raspberry pi.
And now its time to plug in the 8-track of 'Look What They Did To My Song, Ma'.
The piano wont play it no more.