Hi,
I also have noticed confusing changes since sysklogd-2.2.0 upgrade.
I use a configuration for /var/log/messages and /var/log/syslog quite close from slackware stock.
Code:
*.info;*.!warn;\
authpriv.none;cron.none;mail.none;news.none;daemon.none;auth.none -/var/log/messages
*.warn;\
authpriv.none;cron.none;mail.none;news.none;daemon.none;auth.none -/var/log/syslog
cat /var/log/messages* | grep " kernel:"
gives nothing since the upgrade. All kernel messages arrive now in /var/log/syslog.
My FW is configured with log level "debug", "dmesg -l debug" output the messages as expected but messages also go to /var/log/syslog.