Wow, can't believe how bent out of shape some people are getting about the Simpsons stuff. I mean, as a parent, I understand that you don't necessarily want little kids watching the Simpsons. But honestly, I don't see how it is much more inappropriate than Lord of the Rings, or even Pirates/Lone Ranger. I haven't seen the Lone Ranger, but I've heard it is pretty dark in parts and definitely not little kid appropriate in those instances. Our daughter really took an interest in Hobbit/LOTR stuff late last year/early this year, but I wasn't letting her anywhere near those movies yet (I did let her watch the Shire parts, which are her favorites anyways). Same type of things like Pirates of the Caribbean.
I guess in a way, LEGO was a safe option for her to explore that world. The Orcs aren't scary to her in LEGO form (we also have the game for Wii), and it was a way for her to experience LOTR without seeing the movies. I guess the issue with Simpsons is maybe a bit different, since it isn't because of scary images but more about crudeness, but I don't see how you'll see much of that in the LEGO lineup - aside from maybe having Moe's or the Duff plant or something.