IMHO the confirmation that the character has no vagina to be considered newhalf causes inconsistency the most. While I understand that futanari is the most popular therm, tagging futanari only if you can visually confirm the presence of female genitals and newhalf if you can't would work better with the TWYS rule then prioritizing the futanari tag (sometimes tagging what you don't see..).
It's a big change, however, and hence the worse solution for gardening.
Anyway, I think right now it's more relevant to remove the futanari / male_futanari implication.