Model:Personally I think that they'll be visually Humans that appear to be in a stage of Rigor Mortis, with the white eyes lighter hair Colors and more regal looking hairstyles, facial hair and jewelry, as well as a few customizations that harken to regular Forsaken's options like the metal jaw and belts on their face

Armor: They'd definitely have a heavy Lordaeronian theme, with the black & white with gold highlights that Calia has

Personal Theory: I think that instead of being Lightforged they'll be given a nature similar to Naruu where there is a chance for them to fall to shadow

Racials: I think they'll have a racial that benefits Enchanting, one that deals with their switching between light and dark, and one that causes damage based on which side they are on currently