I don't find aestetic customization all that important. I've never been compelled to unlock each and every piece of armor in the Halos. I've never dyed a piece of clothing in Fable. I'll take function over form any day. That being said, there were definitely helmets in Halo that I liked more than others, and I did wear ones I liked. There's really no downside from the player's perspective to having additional cosmetic items.