I agree. Just because something doesn't seem to work at first doesn't mean you should give up on it immediately. Great things are never easy to accomplish. They take lots of work. You have a nice idea, but maybe you could modify it a bit. Here are some suggestions I thought of when reading your plot description.
1. Give more development bewteen Chomper and Sally. It is true, Chomper is a huge exception because he is so small and young, but Sally would probably not be so welcome in the valley. It would make a lot more sense if Chomper tried to hide Sally from the others and Cera found out and threatened to reveal her. That would cause conflict between her and Chomper and would give him a motive to leave the valley to find a home for Sally.
2. The description you had of Scarry tearing flesh off of Chomper's leg seems a bit too graphic in my opinion. I realize I probably shouldn't say anything about violence because there is some violence in my
Revenge stories, but violence can only be tolerated at a certain level. Instead of describing it the way you did, try toning it down a little. Scarry could scratch or cut Chomper's leg and it would still give the image without the extensive violence.
3. If you intended for the story to end this way, then completely disregard this last suggestion, but I think the ending would be too depressing if it just stopped with Chomper losing Sally. Maybe after the battle if Chomper tried to win her back it would keep the pace of the story moving. It's always a bad idea to have a high action or suspenseful part in a story and then just stop it without really expanding on it further. If you want, you could even end it the way you thought of, but make it like a cliffhanger to lead up to another story. This would leave countless possibilities for you to work with.
These are just things I thought of, but then again it's your story so you write it however you please. If you need help or any more suggestions you can always ask me or anybody else who has written a fanfic. You have a great idea, you just need a little work on it. I hope you decide to stick with it because with a little work you could have a great story on your hands
