> breaking compatibility with existing standard and protocols, used not only by Linux systems, but by almost everything else,
Yeah, except that it doesn't. From said document: "Data can be generated from a variety of sources: [...], userspace messages generated with syslog(3)"
> coupling journald with systemd, thus making it non-portable, thus locking out non-Linux systems, all Linux systems not using systemd as an init replacement and most appliances,
If this is a problem for you, then use something else. Just don't expect Lennart to make his life harder by supporting non-Linux and non-systemd boxes.
> using *undocumented* binary format for storing compressed and possibly encrypted and/or signed data.
Why would one document a file format that isn't stable and may be changed in the future? Especially when you can just use the library to read it...