Brian,
Great article!! It has been years since I thought about this battle. We studied Kadesh in detail when I was in school. It is a great example of a documented ancient battle, and you bring the propaganda angle out beautifully. My instructor always said this battle was great because both sides thought they won. They therefor wrote about it in detail and you could compare the sides with some accuracy. If one side had been thumped heartily, like you said, only the victor would have written the story. Here we have two victors, and a treaty to study. Excellent article.
It always reminds me of Napoleon's campaign in Egypt. When he decisively beat the Malmukes it became, "the Battle of the Pyramids!!" Even though the Pyramids were miles away from the battlefield. It just sounded so good, why not use that to enthrall Europe!