I think the shots make one thing pretty obvious: The used mesh is unable to compete with real modeling.
Just look at the grand canyon (I guess that's what it's supposed to be). In reality he canyon drops almost 90° from the rim (sometimes even more!). In the screenshot it looks like an normal steeper valley. Same for the actual river-bed of the Colorado-River. It's a very narrow deep canyon for long distances. This is completely missing.
Also check out the rivers in Shot4. They are evenly wide from the spring to the point where they end in the ocean.