I've just been thinking about this, and it will remove formes that are functionally different and have different roles, such as the genies and their Therian formes. This is probably actually more detrimental than showing formes with no movesets, since that makes little difference other than extending the list a little, but removing functionally different mons unnecessarily limits the results by excluding potentially viable options. I'll have a think about other options, and I'll hopefully have something by the time my holidays start in a week and a bit.