Michael Ausiello with information on John Winchester's faith. Will we get to see more of Jeffrey Dean Morgan?
Yes, we will.
According to Michael Ausiello, "[…] exec producer Eric Kripke said that, and he's standing by his words. 'John Winchester really is dead,' Kripke insists. 'But the show is called Supernatural, and characters can come back in all sorts of ways. In the short term, we want the boys to deal with their dad’s unexpected death, and all the drama and angst that comes out of that, so we won’t see John for a little while. But this isn’t the last we hear from him.'[…]".
Source: Ask Ausiello, TV Guide.