We are always open to expanding or rearranging subforums. We do believe that content should drive the categories and if there are only a few threads on a topic it wouldn't warrant its own. A localized up tick in traffic on a topic isn't what we look for, we look for longer term, consistent content about a subject.
It is better to have a mildly attractive topic in a larger more diverse forum than it is to branch things too much.
"First you start with a pound of bologna..."
-My Grandmother on how to make ham salad.