Most of the clutter I've identified on the MR Discussion forum are threads that are essentially 'low fare requests' masquerading (probably not intentionally of course!) as MR requests. If THOSE threads could be bundled off onto a new forum/subforum 'Low Fare Requests', I think that MR Discussion would be a major beneficiary, aloong with the 'Budget Travel' forum.
No forum on FT is meant to be a quasi-travel agent/consultant, yet those requests come in on a steady basis. Since such requests persist despite stickies and other members and Mods posts not to do so, it might be that creating a new 'Low Fare Request' forum (ghetto?) might be an effective fix to streamline MR Discussion.