I think Lulu really incapsulated the "spirit" of a black mage. She had a venom tongue, especially towards Wakka. She's slightly condescending to some people, her hair is all mystical and everything with those pins, and she carries a voodoo doll.

They clearly styled her with voodoo in mind in FFX, and I loved it. I also like the belts too. That was very bondage.

Lulu just felt right as a modern black mage. It'd be like having Yuna be a black mage. It doesn't feel quite right. Lulu, just from looking at her, was THE black mage. And she needs no pointy hat to do it as well.