I'm not saying its a replacement. The model is suitable as a replacement i.e. inspiration should be taken from it.
What? Daemontools provides a nice utility for logging a process stdout/stderr to a file. That's it. That doesn't come close to the problem that journald tries to solve.
It guarantees that the logs are stamped externally, are committed to disk and that the logs haven't been tampered with by isolating them from other processes and user accounts that can modify or write to them. Don't need journaling on top, just separation of concerns.
Indexing - don't need it. No one does. That's an external problem solved by syslog collectors like Splunk. As someone who deals with up to 500Gb of logs a day, I know my shit. Systemd doesn't solve a thing here. In fact it adds overhead to a solved problem.
And here comes the mythical "coupling is bad" statement while completely ignoring the problem. No, I don't want my NFS daemon to be started before my network connection is up, thank you very much.
Well what the hell does your NFS daemon do when your network goes down, your adapter gets hotplugged after a failure or someone falls over the cable? There is so little of the problem solved by systemd it's unbelievable. The RIGHT solution is to make the processes resilient to failure conditions like this.