I hope this warrior diet is a good diet, and the things in your description that make me cringe are just marketing gimmicks. What was the average life expectancy of a warrior at the time and place this diet was based on? Likely under 35. Your description makes it sound like the diet's creator started with a bad premise and unhelpful constraints and used (hopefully) good science to hill-climb his way to some local maximum in some scoring function that's hopefully not particularly far from the global maximum in that scoring function.

An appeal to nature is a terrible line of reasoning that underlies way too many diets I hear friends promoting these days. The usual implied or explicitly stated premise is that there was some time and place of peak human fitness in the distant past, brought about by evolution, and we should return to the diet of that time and place and apply scientific methods to improve upon that diet.

There are at least 3 huge flaws in using evolutionary arguments to base modern diets on what humans ate thousands or tens of thousands of years ago. Let's start with the flawed premise that after the explosion in variety of foods available when we learned to domesticate both animals and plants, that evolution rapidly converged within a few thousand years the human body to be optimally tuned for all of the foods available at whatever time the diet's creator has chosen. (1) A human at the global optimum for a given diet does not imply that the diet is a global optimum for the human. (The implication arrow goes the other way. Evolution has not optimized plants and animals to be the most fit food source for humans.) (2) Evolution tends to converge to pretty good working solutions, not optimal solutions. (3) There hasn't been enough time since human domestication of animals and plants for evolution to produce more than a hand full of adaptations.

The only two human dietary-related beneficial mutations I'm aware of in the past 10-15 thousand years both happened to have arisen in Europe. One is a mutation that makes a high wheat diet less harmful and the other is a mutation that causes toleration of lactose late into adulthood. The way some people construct diets, they would then start with the premise that people whose ancestors mostly came from Europe should mostly eat wheat and dairy products. The diet creator would then do some reading of dietary studies to scientifically improve the quality of the starting diet to some local maximum based on some set of starting constraints and some limit of research effort. This might actually produce a decent diet with whole grains, yoghurt, and lots of fruits and vegetables added through a healthy dose of hand waving combined with good scientific research.

It would be much better to throw out the flawed starting point. If you're going to pick an arbitrary time and location in human history as a starting point for constructing a diet, don't pick a time and location that had a life expectancy less than half that of modern first-world countries. If I were to design a diet, I would probably look at modern diets in countries with the highest life expectancies or lowest rates of whatever diet-related maladies you're trying to avoid, and scientifically improve the diet from there. I might even try to find a set of countries that had very different diets and yet all ranked highly in my selection criteria and try to find commonalities in their diets as a starting point for designing a diet.

EDIT: I should point out that there are cases where an appeal to nature is a reasonable line of reasoning, but I have never seen such in the context of diet.