>>3782016 (OP)>open worldMany already are and are poorly done.
>dmc/ninja gaiden/platinum combatNo, that is for a certain type of game with an entirely different focus. They are almost exclusively combat and combo focused with only some brief padding in the form of light platforming to break things up between encounters. They also don't use randomly set up encounters, but fixed custom ones.
>cell shaded anime graphicsMost devs can't do it properly and even when they try to use anime style models, they tend to go with default non-custom lighting (which you need for both characters and the world) which makes everything look shit. Not to mention realistic looking environments and textures.
>coopMakes very little sense in most RPGs and makes deciding what to do, going through dialogue and story and so on often very awkward unless both players are perfectly aligned, which is very rare.
>sandboxMore often than not just a meme and not done properly.
>heavy focus on combat and combosMeaning it's not an RPG, but an action game.