The answer, as we're sure you'll agree, is obvious: The complete works of Hayao Miyazaki. Can't you just see it? Princess Mononoke squares off against Nausicaä of the Valley in an all out, over the top, no-holds-barred battle for cinematic supremacy! Laputa Gardener Robot vs. Ō-Totoro! Kiki vs. Porco Rosso! Yubaba vs. Moro no Kimi! There can be Cat Bus DLC and everything.
Hell, No Face is practically in BlazBlue already. Let's make this happen, Arc System Works.