Following plugin properties are missing from the new Plug-in:
javaplugin.maxHeapSize
javaplugin.proxy.config.bypass
javaplugin.proxy.config.list
javaplugin.proxy.config.type
javaplugin.vm.options

Though it's not effecting the applet behavior but could be termed as regression if any application is using it. Out of these javaplugin.vm.options seems to be pretty important and should be implemented at least.