MANY SPOILERS AHEAD
Yeah, I wasn't disappointed, because I didn't expect anything spectacular. It wasn't bad. It was . . . meh. I was a little miffed that on Tuesday (or whatever) the boys defeat God, and on Wednesday Dean is killed hunting a rando vampire. I was amazed at the lengthy speech Dean was able to give while impaled, but you know, tears, I guess.
If I were writing the same scenario, I would have shown some time passing between their defeat of Chuck and Dean's Final Hunt. Show them taking down a ghost or two, a werewolf, a few other vampires, whatever. Show them getting back to "the family business" for a while. Then, during one of their routine hunts, Dean is killed. I would have made the death quicker, without the long speech. Cut to Dean in heaven. It's quiet, peaceful, clearly the Pacific Northwest. Bobby is there. The Impala is there. Bobby smiles, says, "Hey, Dean." Cut to them sitting with a beer, saying next to nothing but looking peaceful. Then Dean says, "Gotta go, Bobby," and he drives off. Then we skip the stuff with Sam and his family (and, yes, wtf was up with showing his wife as nothing more than a silhouette?). We don't need it. We just skip to Dean stopping on the bridge, getting out, and then realizing that Sam is there. They hug. Dean says, "How've you been?" Sam says, "Good. It was a good life." Or something like that. They sit on Baby, looking happy. FIN.
That would be a lot shorter but a lot more effective, I think. This could have acted as the end to the episode where they defeat Chuck rather than its own episode.
If I had to choose some other scenario, I LOVE the idea of Chuck appearing at the end, still writing. It was all a game and he's still there. I would be fine with that, because I didn't like all the Chuck stuff in this season at all, and that would kind of complicate it.
My head-cannon is still that season 5 was the end of the show and the rest is non-cannon. I'm not sad about the long ride, but it is a little sad to see it come to an end (even though it was past time).
I will say, there was a moment at the end where I'm pretty sure the hug between Jared and Jensen was 100% genuine. I could almost see the moment when they weren't in character anymore. Or I'm fooling myself, lol.