Do you think it would be a good or bad idea if the main villain from the first movie were brought back?
I admit that I don't see how it could work, as Petrie should have died had he survived. However, it might be a nice finale ending to have a full grown Littlefoot confront him again. Perhaps he'd go for Ali and Littlefoot would have to fight to stop from losing another woman in his life to the villain.
Perhaps the Prehistoric Pals as grown ups could fight off Red Claw, Sharptooth, Screech, and Thud working together.
However, Sharptooth's return seems hard to swallow, so I created my own villain, Gallim, who also has ties to Mama Longneck's death for my own finale as bringing back Sharptooth seemed so hard to explain why he was still alive.