I think the text/font makes it look flatter then it really is. Try working on your text (eg. resize and reposition) Also to help depth, do an gaussion blur 1 px. and erase over the render and some various parts by him. Then do a sharpen-sharpen on another layer and erase over everything besides the render and some other various parts. This will help the render stand out more.
It's definitely not bad. the text placement makes it look flat like they said. Change that and I bet it'll look real nice.