To protect the quality of the thing you like and that is not difficult of a concept to understand. I actually like Predators and The Predator but they are clear quality issues and given a choice between doing something right and not doing right and putting out decent some of us would pick not doing it. The final episode of Lost and Game of Thrones did nearly unfixable damage to franchise. Think about that one or two episode mess up perception on 7 great seasons. Sometimes ending while your ahead or not putting out something is better for a project.
Give the franchise a break, Wipe the slate clean, Tell your strongest story with threads to put in to build out for the future. If doesn't work maybe your franchise is not a "franchise".