I don't see any characters models being mirrored or flipped, at least from what I've seen in the 3DS footage. Whenever they face left, their back is towards the camera, and whenever they face right, you see their front, that way they always have their dominant side (Right Hand or Left Hand) in front ready to strike their opponent, but hasn't it always been this way? If they were being mirrored or flipped then wouldn't they always be facing towards the camera?
EDIT: Oh on the Wii U version they always face towards the camera, that's so lazy! Hope they fix this, except for maybe Megaman who it actually makes sense with.