In fact, I don't feel systemd generates many complaints. Surely it does generate complaints. By many? I think we're dealing with a very vocal minoroty here. And of course bugs, like any orther package. Around me (I'm a professional Linux sysadmin) I hear everybody to be very happy with systemd in general. It solves so many problems in such a nice way.
I however do understand the complaints. Traditionally a sysadmin keeps his systems stable. Change is never good in the eyes of the sysadmin. Change always is the enemy of stability.
However in a modern world of ever faster change, such sysadmins are growing obsolete, fast. And they're getting increasingly frustrated with the world around them, which they understand less and less. I don't care how your systems worked a decade ago. I want to work how your systems will work next month. Please don't live in the past.
Wayland suffers from the same category of nay-sayers. Please, install Slackware and be content with your obsolesence. And don't come shouting at the people and software you don't understand any more.