Let's not pretend everyone has issues with systemd. Plenty of people are totally ok with it.
Until they have to debug a boottime issue (which crops up quite frequently in production environments with systemd). Some overworked desktop/power-management developers and lazy devops folks have been seduced by the promises of systemd, but all it takes is one morning wasted tracking down boottime issues within binary logs and quirky systemd corner cases to make it clear just how bad an idea systemd has turned out to be.
Unfortunately, by then their strategy of subsuming other projects (sianara ntp, it was nice knowin' you), enforcing dependencies, making it more difficult to maintain alternatives (dropping support for biosdevname=0 for example) will have made it difficult if not impossible for those who wake up to switch to something that adheres to more sensible unix norms. I have used Linux since 1993, on my desktop since I could get X running with twm, and later through the gauntlet of enlightenment, gnome, KDE, e17 etc., but I fear this really is the beginning of the end for Linux as a viable alternative to anything. Unless of course Google steps up to the plate with a solid alternative (after all, they don't seem to use systemd in chrome OS). OpenRC is great, but with power management developers refusing the support anything other than systemd, it faces an uphill battle despite being a well established and in most ways a superior init system.
Perhaps the Debian Fork, Gentoo, Funtoo, Arch without Systemd, etc. will succeed in joining forces to maintain a sensible alternative or two. Because otherwise you might as well run OS X ... you get the same byzantine init and config crap, without the other hassles that in the past were worth it to run a clean Linux system, but certainly aren't with systemd in the mix.