Oh yeah--people often forget that if it wasn't for Christopher, all those copies of "The History of Middle Earth" and the publication of "The Silmarillion" that a lot of us Tolkien junkies hold almost as dear as the Lord of the Rings itself--those things would not exist at ALL. Christopher Tolkien should get SOME credit, c'mon now. A lot of the depth and texture of middle earth was only brought to life VIA those early texts, through his explanations and efforts in editing and research. To say he's simply content to rest on his laurels is kinda shortsighted. If he wanted to rest on his laurels we'd see the kind of merchandising onslaught we see with, say, Star Wars, or Star Trek. Because there's nothing easier than licensing out the brand name and getting fat off residuals.
His opinions are not his fathers as to the adaptability of the stories. And since it's his responsibility to oversee the rights to his fathers estate, it makes sense, from his point of view, to protect those rights to ensure his estate, his legacy, is not somehow muddied. It's not like he doesn't have precedent: Rankin-Bass and Bakshi pretty much smeared feces all over every page of the text--that is, the pages they didn't tear out with their teeth. He had no say in the LOTR film rights--his father already sold those when he was alive. But somehow, he apparently has some say in The Hobbit's film rights, and since he has knowledge his father never had concerning the adaptations of his work, I think if I were Christopher,it'd make sense to me to say "nah, you had your crack at it, i'd rather let my fathers work stand on it's own, without outside interpretation and adaptation."
I disagree with the decision, but I certainly understand it.