(first post, yay!)
Organization can only help so much..although I would be in favor of adding a section for fares originating from outside the US--I'm crediting to MP but will be based in Europe most of this year, despite how it might fragment listings and lower the visibility of reversible fare possibilities.
I would suggest that the forum software itself is the main limitation. Tags could be helpful, sure, but we're really limited by 1) transparency of the fare rules and 2) our ability to categorize fares. It would be nice to have a system that could have the entire fare loaded into the topic as support sorting by carrier, destination, and origin, and have a concept of permitted routes and MPM rules, and -then- a discussion thread under it. But that's probably a bit futuristic.
That all said, tags could be a useful start. Also, the ability to sort the thread list by date started would help immensely (is this available?).