I agree the movies are a little dark. But you should see what other movies are marketed to kids. It's awful. Look at Fantastic Four. It's PG-13 (my 14 year olds have only seen one PG-13 they are so bad) and is marketed in Toys R Us! There really are so few movies that are good for the whole family.
I for one was happy these are there for all of us to enjoy. No sex, no graphic violence, hey, a little troll snot, but you can't have everything!
Back to the subject of Harry Potter, my son has already finished his first reading of it, and starting it over again. I don't think he played video games all weekend! I am just starting it, and I am thoroughly enjoying it so far. (We bought two copies)
I'll bite, what was so horrible about Fantastic 4? It seemed really tame to me.