I currently have waist length hair. My hair gets really curly when it is short, and I actually have to do stuff with it. Long hair is much more low maintenance. Stick it in a bun or french braid if it needs to be out of my way, in a ponytail or regular braid if I'm running out the door, and it is done.
I could certainly stand to lose some weight, but I don't think my long hair makes me look frumpy.