CLI and console shows only properties defined in .xml configuration files. System properties propagated from command line using -D, -P or --properties args should be visible too. It would be useful for administrators when searching for possible problems, the same applies to devels. For domain I'd like to see sysprops on each instance and separate overview for DC.
Previous versions of AS/EAP provide such overview in /web-console/SysProperties.jsp.
NOTE: JVM based properties like java.vendor etc. would be beneficial too.