But anyone else not like wearing head armor?
I play in First Person so I never see my character's head, or face for that matter.
However, there should be a choice between Shield and Helmet to get the bonus for wearing all the same armor. To that end, the Perk should not increase protection, it should increase Speed or Agility with a matched set. While having armor that matches could provide more protection, it seems to me that it would make you move easier as the pieces fit together better. I only say this as I was once helping a guy make some armor and when the pauldrons were not matched to the curaiss, my arms would not move as well or at all.
Even Speech would make sense as you would be more styling in a matched set, so people would want to talk to you more.