Hayley is hardly the first racer to overpack. I distinctly remember past racers also carrying at least one hair-drier in their packs. Usually what happens is that teams shed more and more of their belongings as the race progresses. She also seems a lot more competent, driven and motivated than some other past and present racers.
It is true that she comes across as nagging. But editing is a powerful tool to form our impression of racers so without knowing her personally I wouldn't draw any firm conclusions. The same basically applies to all other racers as well.
