I was told that some improvements were being developed for delivery queues some months ago, but I've have not found anything new in the last releases.
My suggestion is to improve the web interface for "Delivery status" to let you access the messages in the queue for the domain, like you can do with command showrecipients. And with this web view you could perform actions in the messages, like delete, bounce, deliver or submit as spam not detected to TOC.
In the last weeks I'm having thousands of spam messages to aol.com or yahoo.com for instance and I'm getting blocked by them, so I have spam in the queue and it's quite annoying to delete them with deleterecipients, because I have in the queue also legal messages that have to be delivered.
Thank you for your attention.