There are some issues with syslog. Fortunately an extension is ready: http://www.graylog2.org/about/gelf - can be structured and is not limited in size anymore.
Tbh, I haven't seen any standard syslog daemon supporting structured messages - except for apple's syslogd and syslog-ng. Others mostly cut the message to 1024 or so bytes and each one handles new-lines in a different way. So far it seems noone is sending messages that way and noone is expecting them. If a new protocol is the way to push structured logging forwards, I'm all for it. It doesn't mean those two protocols cannot coexist. It doesn't mean a typical logging pipeline cannot include syslog->gelf converter which adds annotations / parses the message.
It also seems that the structured messages handling assumes the message fits in a packet and can be processed dropped when convenient depending on its size. That's not something I expect from a logging system. Gelf adds chunking / compression just in case.
rsyslog also supports structured RFC5424 messages. Others will support it in time.
I agree it's not the most perfect format, but it's usable, and already much better than freeform text messages if you intend to do programmatic processing.
