Anyone reading this who cares about Supernatural knows about the showrunner deal. We had Kripke for 5 glorious years (with several missteps regarding episodes, of course, I'm not saying he was perfect) but overall, especially regarding the arcs, it worked. It was magic. Then he left (which was fine!) and we got Sera Gamble.
I was thrilled when Sera stepped up to the plate in season 6. She'd written 22 episodes in the first 5 seasons, was credited as a producer, and I felt she knew the boys. I was completely confident in her abilities.
Now, I'm not saying she's awful or the show was terrible under her reign or that she kills puppies. (Technically, that was Ben Edlund who killed the puppy in Repo Man.) I still think that Sera is a very good writer, and it remains she's written, alone or in pairs*, some classic episodes.
However, I don't feel she was cut out to be a showrunner. I felt the seasons as a whole were not up to the same level they were under Kripke. I'm not comparing their styles, just the quality of the season arcs and whether they worked or not. I also think she got burnt out by season 7 and had nothing left to give, but I'm not committed to that opinion.
Jeremy Carver is returning for season 8. He's got kind of the perfect mix right now: he was on the show for 3 seasons, and wrote some fantastic episodes (the Christmas special, Mystery Spot, In the Beginning, The Rapture, Free to Be You & Me, Changing Channels, and Point of No Return.) Not only did he write these episodes well and make them eternally memorable, many of them played a large part in the season's arc, and he knew the boys. Anyway, he was on for three seasons and knew these characters. Then, he went away and worked on another show for two years. Not only did he work on another show, he ran it! So we know he's cut out to be a showrunner. He knows our beloved characters, has experience running a show, and has been away so he comes back with a fresh perspective. That seems like almost the perfect mix. (I say almost, because nothing's perfect.)
I'm excited for Carver's return, but it's not without trepidation. I don't expect him to be Kripke (no one can be Kripke but Kripke and no one should try); I want him to take the show and the characters we know and love and show us the way he thinks it should go.) He has a lot to live up to and he has a lot of hopes placed on him by the fans.
Unfortunately, being a showrunner is very different from being a writer. And just because someone is a good writer, that doesn't mean he or she will be a good showrunner.
We've had so many shows where the creator left before the end of the series and the show was worse off for it. Usually, though, there were more issues behind the scenes and the creator left a mess behind for the new showrunner to "clean up," of which they made it worse. (In one case, it got a little better before the end, but the first half of the last season was a joke.) In the case of SPN, Kripke left after a beautiful season, and handed it to Sera Gamble on a platter, saying "I've taken this baby as far as I can; now it's your turn." I think that Sera did the best she could; I'm definitely not saying she slacked. I just don't think she was quite up to the challenge that we all believed she was. (And by we, I mean fans, Kripke, and Gamble herself.)
So I have high hopes for Mr. Carver, but I'm also hesitant. I'm optimistic but realistic.