Well, I'm also a member on PHO, and for their threads, you can add a description, which is a small little bit of text underneath the thread, displaying a chosen message. I feel PC should implement that.
Also, I feel, that the owner of a thread should be able to change it's name, for example, if someone had a hack, and wanted to change the name, they might not be able to because they can't change the name of the thread.
I've seen forums where it's used and it works ok for them forums. But most titles on PC are pretty straightforward on what the thread is about (if not the title then the first post). So would it really be needed?
Send a PM to the Mod of the forum for that. If the forum has no Moderator PM a Higher Staff member.
@Suggestion 1: Hover over the table of the thread and the first few lines of the post is shown. I think that's a lot better than a summary underneath a thread, and I try to make my posts points be known in the first few lines for that reason and spend the rest of the post elaborating.