All good points, some I agree with.
Only things I'll add. (Reasons why I'm dissatisfied with this season.)
1. In the second half of the season, Dean seems to be just drifting from episode to episode.
2. The Lucifer/Kelly/Nephilim storyline is my least favorite of any storyline in the history of the show.
3. I don't like Sam, so I don't really care about his storyline, but I agree that it's difficult to understand his motivation with regards to working with the BMOL.
4. I found the first few episodes interesting and I was more than ready to see how the relationship between Dean and Mary would evolve, but I've since lost any sympathy I once had for Mary, so the character and her relationship with Dean no longer interest me.
5. "Regarding Dean" is my favorite episode of the season, so far. I also liked "Asa Fox" and certain Dean related moments in a few other episodes, but for the most part, most episodes haven't been all that great, in my opinion.
6. I like Cas, but unfortunately, he's tied up in the Lucifer/Kelly/Nephilim/Angels storyline, and as I said earlier, I dislike that storyline. It would be nice if they included Cas in more MOTW episodes.
Maybe the last run of episodes will change my mind, but if not, hopefully next season will be better.
Overall, for me, this season has been less than satisfying.