I've made it so that when someone deletes their own post it is still viewable, including the comments. The post author and body will NOT be visible. Deleted posts will not show up in communities, search results, etc just as before - you need the URL of the post to get to it. Bookmark a deleted post within 7 days or it will be deleted for real.
Ask your instance admin to upgrade to v1.4.4. Chances are they'll be on 1.4.x already so this will be easy for them.
My real goal would be a way of having the option of removing content that needs to be removed, without taking away genuine conversation and replies that were made.