How is Kennedy having consistent trouble? She's fired one group of directors, but that's it. Sure Rogue One had a few problems with its director, but that could happen to any film. Honestly I don't think enough has happened to say that Kennedy is having problems.
Yeah, out of four movies, this is the only one which seems to be having serious issues. Not a bad record, IMO.
You're forgetting the firing of Josh Trank and the Gareth Edwards/Tony Gilroy Rogue One reshoots.