After reading the book, assuming you did so after seeing the movie, did the beginning seem very rushed the next time you watched it? It was like 25% of the book happened in the first 15 minutes of the movie. So much more made sense though, and I understand why Goldman made the changes and omissions he did.
You also have to factor in that Buttercup's chapter was five billion pages long and Humperdink's was like two, and most of Buttercup's was just "When Buttercup was ten, such-and-such was the most beautiful woman in the world". It would have taken much more casting on Goldman's part if he had've done the whole beginning because you have the random village teens and Buttercup's parents and Count Rugen's wife and all of the ex-most-beautiful-women-in-the-world and their counterparts, so it seems a bit tedious to cast all of them.
However, the movie did leave Buttercup to appear "weak and small" because of Goldman's directing choice to not add in that Buttercup was rather ignorant in the book. If you read the book, you would know that she wasn't the brightest bulb in the box, but if you hadn't, which I'm assuming most people have not based on the other message boards, she would appear as weak, specifically in the fire swamp scene.
I think the books does some things MUCH better than the movie, mostly the character of Buttercup. The movie is a movie, so it's paced differently and I think it's important that everything happen as fast as possible, especially up until Wesley and Buttercup are reunited outside the fire-swamp.
I do love the ENDING of the book more though.
I showed this flick to a friend of mine and she noticed how poorly treated Buttercup is. Check out our review here: https://youtu.be/Ldmi1UeMKd0