I've managed to avoid a number of spoilers (except one about a certain character returning, ah well) so I won't watch this.
My guess about capes though is it could well be a modelling/physics thing. Capes are harder to do, I'd assume (not being a modeller) but the bigger problem is having them move dynamically. Either you have some weird solid thing that has no relation to character movement, which wouldn't be worth it, or you have one that flaps and sways as you move, with some semblance of inertia and fluttering. The poor consoles are already struggling under the game itself, two people in co-op wearing capes is probably a lot of extra load on it to handle the calcualtions for physics/rendering.