Whether you want to implement a design, you're not a designer yourself or you're looking for a third party opinion on existing concepts — at some point you need an expert opinion on the subject or you need creative and conceptual input.
I can identify conceptual and design points that make sense and help the graphics team bring fresh ideas to their layouts. It's important for me to understand issues in order to give qualified feedback, so I feed back my input in an equally understandable, clear and project-related way.