Thank you, jacuqelynjack--I confess I wrote that line about the next crazy being worse than Yin because of what Shawn said to assure Jules and make her feel better to think that the next crazy to roll into town won't be as bad as Yin. It seemed like a set-up to make that next crazy actually worse. How?
I think instead of making him or her a bigger killer that they would be a more insidious (more typical) type of villain. Maybe someone who digs up dirt on people that are the good guys (sort of a reverse PI) info to be used to destroy. Maybe so someone can move their own people into their place. Destroying reputations in order to leave the victim alive but destroyed just the same.
Shawn has saved people who have been in this type of danger before--Lassie accused of a murder he didn't commit and Jules in a position of looking bad by letting a prisoner escape until Shawn let her make the final collar--and also when he did some normal PI work of catching a little political hanky panky on film to finally get the Chief permanently installed as Chief. But there has not been any of the main people blackmailed. Although, there is some belief out there that Lassie may use his new found info about Shules against Shawn. I'm not so sure about that but there could be someone out there who could use secrets for bad purposes.
I'm thinking more about setting up a plot line that would create an underlying suspicion with people watching the show (and characters who think they know someone but are having real doubts) about a regular character's actions because they believe they have been compromised. The trust between the characters is one of the most vital elements of the whole show--so that would be a huge issue if that was somehow threatened.
This may sound too complicated (as the movie The Sting was) but maybe it could be a thread of a story arc??? I'm also thinking of the lines between Shawn and Jules at the end of Season 5 when they said that they would protect "save" each other. There was a lot of set-up that can be played out during Season 6. I like the idea of character development and I also like the darker edge but there are probably 50 people against it for every 50 who are for it.
Hmmm.....I kind of like your idea of an essentially blackmail type episode. Interesting. Clearly Yang knows that Shawn and Juliet are together. If there were someone else who figured it out....or who figured out he wasn't psychic and was going to out him, that might be interesting. I'm really hoping that next season brings more regular type episodes and not as many movies. Can't wait until we get some info...though I suppose it will be a VERY long time!