User blog comment:Tommy,Klaus&Kol2012+/ive never been so dissapointed by a story arc in SPN until now/@comment-2605:A000:122A:408A:498A:9BB5:B414:5708-20190412233250

Jack has always been described as an extremely powerful being. If Jack were to remain an extremely powerful being and hunt with the Winchesters, then the Winchesters would no longer need to hunt. The show ends.

They handled this at first by having Jack lose his powers. Now he's powered up. Overwhelmingly powerful characters don't do well as good guys. Good guys have weaknesses and flaws--their struggles in part define them and make them who they are. The audience likes watching relatable characters succeed. When overwhelmingly powerful guys--even those who start out as villains-- fight on the side of the righteous, they are boring and tend to weaken (Lucifer and Crowley, for example). It's easier to make overwhelmingly strong characters the villains. Eventually Jack as an evil character had to occur. (Sam, Dean, and Cas have all had their turns at being .... troublesome.)

I don't think he's evil. After all, Soulless Sam wasn't and Donatello isn't evil, just pragmatic. But Jack is definitely dangerous. He doesn't know his powers and he can't control them. Mary wasn't his first accidental kill. Even if Sam and Dean don't kill Jack, he's too dangerous to let run around. If nothing else, they will have to do something to protect the rest of humanity from any more "accidents."

I understand being angry/disappointed that your favorite character is now a villain. I didn't like when Dean was a demon or when Dean was Michael. But, just as Dean eventually became Dean again, it is possible that Jack will eventually become Jack again, although it may be next season.