I think the development team wants long hair too.
Unfortunately there are engine limitations. I can't pull the specific source post but, the reason we can't have long hair is the same reason we can't have capes. If we did have long hair (and capes) it would be horribly anti-climactic because it wouldn't be able to flow and longer hair (and capes) would look more fake for if they were actually implemented rather than just forgoing them outright.
Not to repeat "it's coming in 2.0" but if I remember correctly the same post I'm "referring" (term used loosely) to mentioned that the new engine would be significantly more capable of displaying such things. Even then, we won't be getting anywhere near the fluidity of say, Lightning's cape/scarf in XIII.
It seems the "hard" ponytail options we get for a lot of the female hairstyles was a compromise. Developers really wanted to have long hair, but couldn't justify that hair not moving well.
In other words, they didn't want vanilla Skyrim hairstyles, and honestly, I applaud them for making that decision. Those hairstyles are atrocious. Love the game though.
