Humm, I kinda like that idea Nathan,
If I understand you correctly, your sayin to have a main topic, i.e. Aircraft, Armor, Sci-Fi/Space Etc. and then have sub categories of WIP, which would comprise (military, airliners) or in the case of armor (WW2, Cold War, or even Axis, Ally, NATO....), then completed builds category, questions category Etc.?
That would probably cut down the confusion, at least on the top layer, keep special interest in their subgroups and DE clutter very large forums such as aircraft and armor.