I really like your idea. I suggest that HN shows the original title first and in a second "sub-headline" in italic letters the "commentary" headline by the submitter. Like:

   A new beginning
                                          
   *PHP elects new leader*                         
                 
                                                                
                                

After thinking about it, here is a even better solution:

Let titles allow to be flagged by the community. Example below:

  submission X by kdzsb 22 minutes ago | flag title | flag discussion | 9 comments

Moderators would simply edit flagged bad titles. Rather than having them to watch all titles (old rules) or no titles at all (new rules).