And two or three episodes in it became clear that none of those writers had a grander sense of the boys "story." It became more "LOOK we're being mysterious" instead of actually being mysterious by NOT trying look mysterious (the way the show rather deftly handled Ruby in it's heyday). It all felt like Sera Gamble sent the writers on summer break with an assignment to each come up wiht three ideas of how the series could continue and then they executed all of them at once. It was awful. None of it made sense. They destroyed the characters and wipes out five years of consistent specifically motivated personalities.
I was listening to an interview once where Eric Kripke banned umbrellas from the set because he felt Sam and Dean would be too rough and tumble for umbrellas... that's absurd! But it tells me one thing that made me very at ease. He KNEW his characters. He knew their nuances their reactions. Everything they did they did because THEY would do them not because it would help the writers get to a point in the story that they think is 'cool' or is necessary but was difficult to introduce. Nothing was forced. Characters lived and breathed and acted and died as who they were and so they felt like peopel and we empathized with them as people.
I also don't think we've seen the end to Cas. They got rid of him way too dismissively.