It's too empty and boring looking
What you've got is aight but it ain't that good you need to add some more stuff like c4ds over the render not saying you should whore the thing just make it less boring like adding some gmaps
It's good and basic.
But it looks plain and boring. The render just looks like some soldiers standing with a gun, and he has no real action. Also the dark colours look to dull which add onto the boring part of the signature.
I suggest maybe adding some effective colours, which corresponds to your render as well.
Your render should be effective, and the colours of the background should be effective, as well.
Try smudging if you can, next time, its a popular option, and the outcome if you do it properly is good.