Its seems that the patchdir server option no longer is really of much use since it cannot be used to patch the bootstrap components itself. There was a new -B|-bootlib option to prepend jars to the bootclasspath added to 3.2 branch and the 4.0.1 release that allowed one to add jars to the dist/lib directory ahead of any bootstrap jars. This has been critiqued as:

<critique>
The problem with your patch, from my viewpoint, is that it uses ServerLoader.addLibrary(). This forces the javax-management-monitor-Monitor-patch.jar patch to jboss-jmx.jar to reside in the same directory as the rest of the boot JARs. That means that I either add my javax-management-monitor-Monitor-patch.jar patch JAR to the ${JBOSS_HOME}/lib directory, which means I'm directly fiddling with the Jboss distribution and I want to treat that as read-only, or I move all of ${JBOSS_HOME}/lib over to someplace under my own control, which means I am over-treating the correction. It seems that if the patch to Main uses ServerLoader.addURL() instead, I can keep the bulk of the boot JARs in ${JBOSS_HOME}/lib and still have the Monitor patch in a directory under my control.
</critique>

I believe the correct resolution is to restore the patchdir option to a behavior which prepends its argument url to the bootstrap classpath using the addURL as requested.