It could have had a happier ending if the main character made different choices. For example, if they chose to forgive instead of seeking revenge.
It could have changed the entire tone and message of the movie. Maybe it would have been less heartwarming or more adventurous.
It could be external factors. For example, family opposition. If the families of the two lovers don't approve of their relationship and constantly put pressure on them, it can be very difficult for the love to survive. Also, distance can play a role. If they are separated by a great distance for a long time and can't find a way to be together, the relationship may fade away.
Some people might think Toy Story 3 should have ended differently because they felt certain characters' arcs weren't fully resolved or they had a different vision for the overall message of the story. Also, personal preferences play a big role. Some might have preferred a happier or more bittersweet conclusion.
It's hard to say for sure. Different people might have different ideas of how the story ideally should have ended depending on their expectations and interpretations.
Perhaps it was a sudden, unexpected catastrophe that came out of nowhere and changed everything. Or maybe it was a slow decline over time due to unaddressed issues and mounting stress.
It could end in a completely unexpected way, like a sudden twist or a hidden truth being revealed.
Sure, there's a chance. Maybe GRRM had considered various endings during the creative process, or external factors could influence a different conclusion.
Authors of Merlin fanfic often do things differently by imagining Merlin in modern settings or giving him a darker personality. Another possibility is changing the relationships between the main characters significantly.
Well, it could be a twist or a new development that leads to a different outcome.
Hard to say. It could be that new characters or events come into play to change the course of the story. Or perhaps there's a hidden backstory that will be revealed.