For the second point, I saw put barbarian hair and antihero hair on the same page. Antihero hair does not have a 2:1 ratio and if we don't get it there'll be a hole. Plus it's basically the same thing anyway.
Okay, as for Samurai Ponytail, I'm thinking these are the key traits:
The hair is long and well kept. It might matter that the hair is almost always black since I think it's a traditional sort of image rather than just a sign of being a cultured badass.
The character at the very least seems rather reserved and elegant
The hair is not free flowing, but rather is bound up in a topknot which then flows down the back.
Trope is gender neutral so long as the other points apply
I think point 3 is problematic; the topknot has been declining in popularity in the last few decades, while the character trait has not. Just off the top of my head, Byakuya from Bleach has some little doohickeys in his samurai longhair, but nothing that would be a real topknot, and I don't think it's really even bound into a ponytail. Like Sephiroth, it's meant to make him look more elegant and noble. (It's worth mentioning that like half the male cast of Bleach has long hair.)
Rorouni Kenshin has a ponytail but no topknot.
Straight? Neat? The works of Akira Kurosawa and Toshiro Mifune beg to differ. Mifune is probably the most iconic movie samurai of all time, and our page image shows him unusually straight and neat (which is to say, not very). He basically showed off his badassitude by being scragglier and messier than anyone else in his movies. :)
Okay, Samurai Ponytail was pushed out the door since it had been stagnating forever. Is anyone keen on picking up Barbarian Longhair? Not really keen on doing it myself since I have a tendency to forget stuff I have in YKTTW after awhile.
Wild Hair signifies close to nature. Barbarian Longhair signifies a badass who is wild and uncontrolled, but that doesn't necessarily have anything to do with nature. For example, the 90s antiheroes get lumped into that category. They're related, but they mean different things.
I could write up a description for the trope if no one else will. I just think someone else should carry it through YKTTW once I've done so.