The policy is illogical.
If a post doesn't fit anywhere else, it should theoretically be in OMNI. And yet there are relatively new forums (Women's Travel and Religious Travel, for example) that have travel related topics that DID fit in TravelBuzz! or another existing forum. Maybe not well, but those feelings are subjective.
Adding a forum should be up to the TalkBoard with adequate input from the member population. Announcements and polls should be put into place to determine the demand of a forum.
For example: It is my opinion that there wasn't enough opinion sought out on the creation of the Men's Forum that was, ultimately, rejected. I'm not saying that the forum should've been approved or was rejected incorrectly, but it didn't seem that member input was actively encouraged, with the exception of the thread on TalkBoard Topics.
As far as removing old forums, it should not be done in a formulaic way. Clearly, obsolete programs should be eliminated or moved to a separate area when the programs end. If there is a request for an airline/hotel/car program forum that doesn't exist at all, it should be approved without much debate in most circumstances.
Removal of forums could be accomplished by a once-a-year review of all forums. Forums could be nominated by TB members and voted on as part of an annual process.
Once forums are approved, though, I think they should be given at least one full year before being put up for removal.