I think in terms of safety, it’s definitely in Dragonflight where it started for me. Legion, BFA, and Shadowlands had more “grimness”, which I personally look for in WoW (but sadly BFA and SL missed the mark for me).
Re DF: I think for example the Djaradin and even the Primalists aren’t exactly giving cutthroat or ruthless. I think there needed to be more murder or sense of danger in general. I also think they shouldn’t be afraid to kill off main characters more.
Not to say though that it always needs to be dark and brooding. The Blue and Black DF stories were definitely the best ones, and were overall a W for me and the best parts of the story.