I like to think that it's the Fremennik way to rock an open helm into battle. A little foolhardy but hey, maybe the brute strength of the Fremennik way pulses through your expression: reading the adrenaline rush on your character's face makes your enemies quake in fear (and the lack of defence gives you extra incentive to hit a little harder).
I would say a slightly lighter colourisation could suggest a higher quality of mineral used and larger/arced wings could be how the smiths say "this is how we're differentiating this model from the last"