The "Devuan" Debian fork and the fuss about systemd

What makes you think that there's a dictator in the systemd project? Looking at http://cgit.freedesktop.org/systemd/systemd/log/ I find at least 6 differenct committers in the past few days. The highest number of commits was by Zbigniew Jędrzejewski-Szmek, who to the best of my knowledge has never been mentioned in any of these systemd discussions.

"and requiring very specific kernel versions that mean you need flag days for upgrades (that aren't documented very well!) where you can't go back to the previous kernel."

Not very specific kernel versions. Just new enough kernels. And you don't need flag days, you just have to make sure, you have the newer kernel before the systemd version that depends on this kernel. Really just like with any other software and its dependencies.