I don't think it needs limiting due to the Other category. That is fine as it is, or they could make an "RP" and a "Social" category to separate some of them from omnicrafters.

Multiple duplicate listings for the same thing could be made reportable as well.

I think what they should restrict cross-DC for is joining public High-End parties via Party Finder. That would prevent people feeling pressured to DC travel to farm an extreme or prog savage, but wouldn't prevent people switching to join a private party for their static.