I guess it depends on your source of info but I've found what came before was pretty comprehensively & accessibly documented, at least as well as systemd, which - while well documented - suffers from sprawl & overwhelm of the docs. There's just SO MUCH to grok in comparison.
No way. I was easily able to create Systemd units from 0-knowledge, where the init system remains a big black box riddled with question marks for a very long time. Very little was documented.
Absolutely not the case. Even relatively simple real world uses involved collections of shell scripts to carefully mount or initialize services in just the right order and would often fail with weird and infrequent timing glitches. With systemd that all becomes explicit, so of course it is awkwardly verbose. That is the whole point and a huge upgrade.
I never found systemd difficult, but I do find prior solutions to be simpler. An init script is easy, and the order is also easy. If people are accustomed to UNIX systems, the sysvinit is better. For people who never experienced those systems, systemd is their friend. No need to use UNIX tools when Systemd ships with batteries included.