What if Ryan Hudson used to be like Nancy solving crimes and getting involved with the supernatural? I've suspected that Nancy's bio mom didn't commit suicide but was murdered and with the black door that could be a real possibility. I think this could have been a good S5 plot especially if it had a Scooby Doo Mystery Incorporated vibe with it coming out there were past mystery solvers meeting strange ends or disappearing. Besides it would really fit for Ryan to have once been like Nancy and I'd have loved for a villain to grab her and say "You are as big of a pain as your father!"

Also, I still think Nancy's bio mom was pushed by someone and they used the black door to cover it up.