If the movie is cast aside to the gutter by critics/fans and the merchandise fails to garner the return that Pierrot was hoping for, there might be a chance for them to backpedal in order to preserve what's left of their credibility. The odds of a rewrite or a deus ex machina appearing from the heavens to invalidate this mess are very remote, but as we know by now, anything could happen.
My selfish side would take it for the closure. I won't support Kishimoto's future works but I would appreciate it if he admitted he was wrong and this wasn't the true ending.