Well as I said shortly after it came out I do think that it could have been a viable two hour movie if they trimmed the kids down to just Spider and Sully's youngest son and removed the whales from the story completely (then Spider could have been the one to do something on the command ship to send people into disarray instead of the whale breaching.)I know you're joking. I bet even you would have liked it just as much at 2 hours.
Not that that is the only way to streamline the story but in my mind probably would have been the easiest. I can't imagine liking that version nearly as much though because I really liked all the kids and whale stuff and thought that everything just paid off so satisfyingly in the end.