For years I had drawn Morgalla wearing a red t-shirt, red sneakers and blue jeans. I didn't want her in a "costume" of some sort.
I think she looks more humble this way, I mean after all she already has HORNS. As the years went by, the shirt got smaller until it was a baby t and sometimes it was purple, too:
But HIGHLANDER comes into being for having a sci/fi-fantasy element in modern-day times with sword fights in the middle of 1980's Manhattan. I love the contrast in hero and villain, MacLeod the "good guy" with centuries of issues and memories to deal with. And the Kurgan looking like a modern-day barbarian.
Macleod is such a contrast to him, not just in personality but also in wardrobe: He's dressed like he just doesn't give a crap:
His wardrobe is meant much more for comfort and for its use fullness. I respect the filmmakers for not making him be a "flashy" character and that shone through I think with Morgalla...just a tiny bit.
Why does she wear jeans and a t-shirt? Because she wants to. She's not trying to impress anyone.