Hmm... it was a good finale, but I didn't like some aspects.
The traditional Carry On My Wayward Son segment made the season look better than it actually was. Bobby's final exit felt a bit flat, and I don't understand how it spurred Cas into helping. The whole leviathan story ended on a whimper too, a bit of a limp dick.
Good hook for the next season though....I expect Cas has gone to find the fallen garrison to help their chances of survival, and next season will hopefully be back to Crowley/Heaven/Hell/God etc. which I'm very happy about.
It'll be weird watching Supernatural on Thursday though.... I kind of got used to my Saturday morning session with the Winchesters.