If you think about it, we have already seen a ton of enemy types. Flying babies, regular dolls, dolls with chainsaws, dolls with shields, big bulky dolls, and two bosses: one that looks more like a hairy monkey and another that looks like a larva with a pretty disgusting face. The problem with these (excluding the bosses) is that they look a lot alike (doll-like) so I would like to see some demons that look more like the first boss hunter demon thing (more organic).
There were stone horses in DMC3, so I can see something like those horses being enemies, though I doubt that's the case there. It looks more like just the world morphing around and the plastic horses flying out of place because of it. But again, I would like to see more organic demons, those horses just look like more dolls to me.