Supernatural should have finished at the end of its fifth season. It end with a hell of a lot of finality, and wrapped up everything that had happened, hinted at or ever talked about. You can't get much bigger than the end of the world. Not just your every day thermo-nuclear war apocalypse either, but End of Days, Heaven vs. Hell. Judgement Day without Arnie.
But Supernatural's ratings were too good, so CW commission a sixth season. But the show's creator, Eric Kripke was done, his five year story was told. So we got a new showrunner and everyone said Supernatural should have finished at the end of its fifth season. Until now that is.
Season Six introduced the Alphas, the monsters that birthed other monsters, Sam was a dick with no soul, and Castiel started to look at the deep end like it was a good place to take a swan dive off. It was struggling to find something to talk about, but heading back to the monsters the Winchesters used to deal with seemed like the sensible choice, but the artificial threat raising rang hollow and it just wasn't interesting.
Season Seven brought in the Leviathan and despite their leader, Dick Roman, possibly being their second greatest bad guy after Mark Sheppard's Crawley and a couple of epic moments that will go down in the series' history, it just wasn't that interesting. You couldn't help but feel that they should have gone out on a high. That no one could think of something to rival what they'd already covered.
I nearly dropped the show several times, usually just watching it through those two years as a ritual rather than actively looking forward to it. Any friends that asked about Supernatural I'd tell them to end at Season Five, the natural ending point, not the undead monster it so ironically became.
Then Season Eight started, and we worried that Dean's return from Purgatory was going to go over the same old ground we'd covered when he came back from Hell, or Sam was missing his soul. But instead the writers finally just moved things on, the Winchesters' have been through this before, Dean's a little harder but lets not dwell. Instead we get a story that finally feels worthy of following End of Days.
We're back to Angels and Demons, we're tackling the fallout from the averted apocalypse and Sam and Dean have an end game in sight. Not just stop yet another crisis, but an honest to goodness chance at stopping all this madness. It finally feels like the series has its identity back, that the Winchesters know what they're doing.
It's taken three years, and another showrunner, Jeremy Carver, coming on with Eight, but finally Supernatural should have had continued after five seasons.