The HOST_CONTROLLER JAVAOPTS are only for the host-controller itself, so unless you want to debug the actual host-controller that is the wrong place.
You can enable the debugging for each server in host.xml by changing the JVM confguration for each <server /> you want to debug, like:
<jvm name="default" debug-enabled="true" debug-options="runjdwp:transport=dt_socket,address=8787,server=y,suspend=n" />