Okay... As a teacher whose students are artists, can I offer some advice on how to give them constructive criticism? Just in case you happen to meet Mr. Reynolds? Or want to effectively lobby for future art changes?
For close analysis, the more concrete your observations, the more persuasive they become. Try to avoid imprecise words like “interesting,” “bad,” “ugly,” “beautiful,” and the like. Such empty words tend to raise more questions than they answer. Try being more specific. Saying the artist is "can't draw people" is not helpful because the artist can't do anything with that kind of vague feedback and will reject it.
It doesn’t matter what you believe. It only matters what you can prove. Have several reasons why your reader should be persuaded to agree with your argument. Have two or three pieces of evidence to support each point. The more specific your evidence to your argument, the more persuasive it becomes. What precisely do you dislike about his humanoid figures? Posture? Head size?
For example: What is the impact of drawing our interest in this manner? How does this observation advance your argument? Why did you find this art not useful as a DM? Elf Witch, for example, made the argument that the cover of the PhB is precisely not the place to use pin-up influenced poses and costuming if the game is going to attract female gamers.
Finally, persuasive art criticism tends to try to acknowledge the strengths and traditions from which the artist springs. Face it, for you to be criticizing them at all, they have to have had a certain amount of success and a demonstrable appeal with an audience. Understanding and acknowledging the artist's strengths makes your criticism more credible and more likely to be heard by the artist or his admirers.