Why hasn't Riot made Blood Moon Diana?

I've just started to play Diana and I think it's stupid that Riot has made a BM Yasuo and BM Kennen BEFORE or even instead of Diana. Don't get me wrong, the skins are cool. But it's DIANA, Y'KNOW, THE MOON LADY? Everything about her is based around the moon, why in the hell isn't there a blood moon Diana? I just see so many amazing concepts and think of how easy it would be to make an amazing skin!