AMC revealed who he is playing in Ghost Rider: The Spirit of Vengeance. He'll be Blackout and it's the first time there has been confirmation about an actual comic villain being in the film. Johnny will be transformed into Blackout half way through the film a very formidable villain of Ghost Rider. In the comics he has many vampire characteristics so I wouldn't be shocked if they go that route in the film.
The film is more of a reboot than sequel as the directors/writers Mark Neveldine and Bryan Taylor are re-imaging the character and his origin. Similar to how The Incredible Hulk was both a sequel and reboot. Yet keeping Nicolas Cage as the lead actor in place. I'm not sure if they'll revealed if this is PG-13 or aimed for an R-rating but from sounds of things it could go either way.