In terms of who should be the face of magic as a whole, I'd like to say Wonder Woman, but in terms of who should be like the premier magical specialist or Dr. Strange analogy, I'd say Zatana. I like the more overtly magical turn they've taken with Wonder Woman and I think it's a great avenue to further define her niche in the DC universe in a way that's not so self-contained and is more inclusive of the rest of the DC universe. on this route, I can more easily see Wonder Woman leading her own major event ala Thor and Batman recently. However, she should stay a more fantasy and celestial type of magical hero, Zatana's the best fit for the mysticism and sorcery side of magic. Snyder's JL hinted toward Wonder Woman recruiting other female heroes as Amazons, that would be the best way to play on that balance; have Zatanna join the Amazons and make that community the face of magic.