To be honest, I really can't say if this movie is more accurate to the book than WWATCF, but it did add certain elements, like a backstory for Wonka (I think Sessler mentioned that), and a lot more character traits for the other grandparents. And I did like elements of both those additions. Two of my favorite lines comes from the other grandpa (damn, I can't remember his name) and the completely senile other grandma ("I love grapes!"). My other is how Willy Wonka's flashbacks are almost as campy as the ones from Wayne's World. I love when he comes back from one, and he's just staring off into space when everyone gets his attention. "Sorry, I was having a flashback." Mr. Teavee asks, "Do these... flashbacks happen often?" Wonka responds, "Increasingly... today."
By the way, I have something I'm trying to remember? Charlie's dad, Mr. Bucket, was in this movie. I seem to recall him having an inconsistent history with these adaptations. The way I remember it was he was in the book, but his character was deceased in WWATCF. Is that right?