I'd love to be wrong about this
If SPN goes where I think it's going--which is irritatingly similar to Buffy S6 with one of the lead characters addicted to magic demon blood and another all emo after being pulled out of heaven raised from hell--then the last episode is going to go something like this:
Someone kills Ruby. My money's on Bobby.
Sam kills Bobby.
Dean gets powered up by a coven of witches the angels and goes after Sam--to either kill him or save him.
We'll get a yellow crayon moment between Dean and Sam but not until next season, when they're both battling Lucifer, who will rise in 4.22 when Sam kills Lilith ["Lucifer Rising" suggests that Lucifer will rise from hell--just as Dean did in "Lazarus Rising"--and Sam breaking the last seal after Dean broke the first completes the reverse parallelism the writers have been working on this season].
I really hope it doesn't go down like this, partly because Buffy S6 is the last thing anyone should be modeling their plotlines on, but mostly because I think killing Bobby is a mistake. Bobby is the boys' last connection to, well, anything in the human world. Without him, they've got Castiel (an angel--no human connection there) and...nobody. Next season, they'll essentially be cut off from the world they're supposedly trying to protect, consorting with angels and Lucifer and probably a bunch of miscellaneous demons.
As characters, the guys need both a father figure and the grounding influence that Bobby provides, and as a dramatic construct, the show needs a Bobby-type character for similar reasons: He reminds the audience why the boys do what they do, what they've given up to do it, and how regular people will see and judge their actions. He's also the morality and sanity check on the boys. How many times have we thought, "Man, Bobby's going to give Sam/Dean/both of them hell when he finds out what they've been doing"? Without Bobby, who's going to do that? No one. And I think they're going to need that more than ever next season.
Someone kills Ruby. My money's on Bobby.
Sam kills Bobby.
Dean gets powered up by a coven of witches the angels and goes after Sam--to either kill him or save him.
We'll get a yellow crayon moment between Dean and Sam but not until next season, when they're both battling Lucifer, who will rise in 4.22 when Sam kills Lilith ["Lucifer Rising" suggests that Lucifer will rise from hell--just as Dean did in "Lazarus Rising"--and Sam breaking the last seal after Dean broke the first completes the reverse parallelism the writers have been working on this season].
I really hope it doesn't go down like this, partly because Buffy S6 is the last thing anyone should be modeling their plotlines on, but mostly because I think killing Bobby is a mistake. Bobby is the boys' last connection to, well, anything in the human world. Without him, they've got Castiel (an angel--no human connection there) and...nobody. Next season, they'll essentially be cut off from the world they're supposedly trying to protect, consorting with angels and Lucifer and probably a bunch of miscellaneous demons.
As characters, the guys need both a father figure and the grounding influence that Bobby provides, and as a dramatic construct, the show needs a Bobby-type character for similar reasons: He reminds the audience why the boys do what they do, what they've given up to do it, and how regular people will see and judge their actions. He's also the morality and sanity check on the boys. How many times have we thought, "Man, Bobby's going to give Sam/Dean/both of them hell when he finds out what they've been doing"? Without Bobby, who's going to do that? No one. And I think they're going to need that more than ever next season.