I was going for somewhere in between, honestly. I know I don't have the skill to try realistic but I wanted to push for it. Here's the diffuse: So push for more highlights and shadows?
I did a quick level adjustment on your diffuse and attached the newly created file. (EDIT, couldn't attach new file but that's how I did it) You had a lot of negative space in your contrast spectrum as shown below.
I think the main problem with your texture is lack of levels; it looks like you're lacking a lot of highs and lows that will help the contrast. Do you mind posting a picture of the texture? It would help with the critique. And is this a diffuse only? What kind of style were you going for; hand-painted, realistic, somewhere…