Now I haven't read the book since it first came out, but wasn't there atleast an explanation for why he's called the Half-Blood Prince?
Spoiler:
You're right actually, there was. But it was Hermione that figured it out and told Harry I think it said the day before the funeral. But if I read your post right, none of that made it to the movie right? Which is really kind of lame. The part I was most looking forward to was everything starting with Harry and Dumbledore coming back from finding the fake horcrux to discover the dark mark.
I think Dumbledore's funeral could have been visual amazing.