As the content is different it might be difficult to show everything.
Also jboss-cli is a management interface and it might be a bit too much to show this, but this are my two cents.
The only way I know is to write a simple queue/topic browser using JMS
My goal was to have on overview of the messages in the DLQ and the ExpiryQueue. I'll follow your advice and put it in a separate tool with a QueueBrowser.