Well, I'm not an expert, and I don't think it looks too bad at this point. As you said, it does seem a bit flat looking, but with a little more texture and, perhaps, a bit of shadowing you could give it more depth so to speak. The one thing I did notice, particularly at the upper-most elevations is that the terracing is showing through a bit. I'm not a Wilbur user, so I'm not sure what, if anything, could be done to fix it there. Certainly, however, there must be a way to work something up in PS (again, I am not a PS user so I can't be 100 percent certain). Still, not bad, not bad at all. My one question would be whether the points where the mountains run right up to the coast line are meant to be cliffs? If this is the case, it might go well if you can find a way to show that better.