Well it looks like MTV's Teen Wolf has found there way to get into Season 6 & 7. Tyler Posey will probably take the show after Season 7, to continue with a younger cast.
Jeff Davis said that he would like for someone to take over after Season 6, but now that Teen Wolf is still the biggest scripted show on MTV he will probably stay for season 7.
Well Jeff Davis might try to bring back Tyler Hoechlin and Daniel Sharman back for Season 6. In Season 7 Jackson, Ethan, Cora and Peter will probably join the cast again.
Season 6 possible/rumored story line: "After defeating one of the biggest serial killers in history. The Ghost Riders arive, with the Dread Doctors still on foot and Theo walking arround. Scott McCall calls for back up. Derek Hale arrives back in Beacon Hills. With Isaac Lahey returning to help Chris Argent and Scott McCall. Stiles has to face the Nogitsune, this will give him side effects."
With the main cast:
Season 7 possible/rumored story line: "After facing Dread Doctors, Ghost Riders, Skinwalkers and the Nogitsune. Scott and his pack can't catch a break. This time not Oni's or Ghost Riders come to Beacon Hills. This time Naguals and Yuxas come to Beacon Hills. Can the pack face this? After Void Stiles if officially over the pack still has to find away to bring the Nogitsune back to make sure he won't turn Stiles again. After Jackson comes back with information on the dead of his parents, Scott accepts him into the pack. Ethan who is still affected by the dead of his brother wants to do the right thing and comes back to help the pack. When something goes wrong with Derek, Cora returns and asks Peter for help. Theo might know something about the Yuxa what might help Scott. But is Theo good now? That's the question, he did save Stiles his life with Scott."
After Season 7, Tyler Posey will take over the show. Colton Haynes, Tyler hoechlin, Charlie Carver, Ian Bohen, Adelaide Kane and Arden Cho will leave the show for good or guest star in the future maybe.
Holland Roden and Shelley Hennig will become guest stars in Season 8.
Dylan O'Brien won't leave the show.
Different opening Credits will be used because of the bigger cast. They have something cool in mind.
Season 8 possible story line: "Scott McCall desides to not leave Beacon Hills and work with Deaton, Stiles gets a job as Deputy. Deputy Strauss becomes a really close friend to Stiles (what we don't get to see, because of the time jump). After Lydia and Malia left for college, Kira died, Derek, Braeden and Cora left together, Jackson moved back to london, Ethan moved away and Peter finally left not much happens in Beacon Hills anymore. Chris Argent and Isaac Lahey decide to stay. Scott and Stiles move into Derek's place together with Chris Argent and Isaac as their neighbors. When a new werewolf (A Hale) arrives into Beacon Hills. A pack of all different creatures get into Beacon Hills. Liam, Hayden, Mason and Brett work together to find some cluess or whats going on. But Liam asks for Scott's help. Scott and Stiles try to make a new pack of their own ready to fight this battle. But Theo might have some trouble fighting this battle."
New rumored opening credits:
Start off with Tyler Posey and Dylan O'Brien together hugging.
After that have Daniel Sharman, Cody Christian and Dylan Sprayberry in wolf mode.
After that have Ryan Kelley in hellhound form and Cody Saintgnue in werewolf form.
After that have Khylin Rhambo and Victoria Moroles in human mode.
After that have JR Bourne, Aaron Thornton and Linden Ashby in Gun mode.
Then the new Hale won't be a regular, Scott's new love interest won't be either.
Melissa Ponzio, Seth Gilliam, Todd Williams, etc will still be in the cast.