The choice of a diet depends on what you want to accomplish - whether you want to lose weight, gain weight, manage a chronic lung disease or kidney problem, protect your heart, or protect the planet.
I think the paleo diet is restrictive. As I know it, since it tries to mirror how humans ate before the advent of farming and fire, it prohibits all grains and beans, even in their whole form, including green beans, peas, and peanuts; all dairy food, butter, cheese, etc.; all fermented foods like vinegars, kim chee, pickles, and alcohol; salt; and all cooking oils (as well as all cooking, although I know some paleo followers have relaxed this restriction). As a beverage it allows unheated, unprocessed water - rainwater or from a surface source (to maintain a particular colonic bacteria population?). I don't think it's a diet that many people can easily follow.
I know it focuses on wild plants and animals. That has benefits. You'd do away with chemical fertilizers (all fertilizers?), pesticides, genetic engineering, fuel for farming, irrigation, and processing, and the whole confined animal feeding operation mess. Meat would have a higher relative amount of omega-3 and less total fat. But here again it's restrictive. Plants like tomatoes, apples, corn, etc. bred to be large, starchy, and sweet would not be consumed. And there aren't that many non-farmed plants and animals to go around. The more you relax restrictions, the more it can be argued you aren't eating a paleo diet.
There's the issue of animal food consumption's larger carbon footprint relative to plant food, the increase in the price of food it causes, and its contribution to global warming and world hunger. That brings me back to the purpose of the diet.
So, the diet itself - wild lean uncooked meats, wild unprocessed uncooked plant foods - has merit for some purposes. It's probably a good weight loss diet, especially if everything is raw. Although it's difficult to judge a diet out of context. Modern man lives in a very different environment than prehistoric man. In fact, Dr. Wrangham argues that modern man (and modern man's brain) would not exist if not for fire and cooking.
One thing it has going for it that I think most people can do - it restricts processed food.