The ancient Berkeley syslog is a functionally impoverished logging mechanism, but the protocol is well understood and widely supported. You can use a modern version of the daemon (Ranier’s rsyslog or syslog-ng for example) and work around the shortcomings of the protocol itself.
I’ve been working with a Red Hat Enterprise Linux version 7 spin-up, and since systemd is basically a Red Hat product it should come as no surprise that RHEL7 thoroughly embeds systemd.
Here’s a section of the documentation that describes how the error logging works:
Some versions of systemd journal have problems with database corruption, which leads to the journal to return the same data endlessly in a tight loop. This results in massive message duplication inside rsyslog probably resulting in a denial-of-service when the system resources get exhausted. This can be somewhat mitigated by using proper rate-limiters, but even then there are spikes of old data which are endlessly repeated. By default, ratelimiting is activated and permits to process 20,000 messages within 10 minutes, what should be well enough for most use cases.