The grey gradient uses a lot of colours and looks automated (to the point where I suspect it might be against PJ's rules) and doesn't really add anything to the piece because it's so subtle. I think it would do better being replaced by a solid colour or a manual 3-4 colour gradient similar to the dark gradients on the sides.
Ah sorry about that, forgot to remove the gradient like I did in the last one- will fix it shortly!