In all seriousness, the Rage Titan was an anime only appearance and not cannon to the story but i think the Rage Titan should have been the titan of choice for that fight as Eren's speech before he transforms is akin to willingly giving up his own humanity. ''Concquenses be damned.''. His titan form should have been more beast like the Rage Titan form was as if the resemble him willingly becoming more beastlike or as some might put it, more monstrous.