For me, there's no bigger sin in TLJ than Canto Bight. Nothing even comes remotely close. I still haven't found one single redemptive thing about it. Nothing! It was pure garbage. The only saving grace is that it took 11 or 12 minutes of total screen time. Some people try to make it seem like it took half the movie. It didn't; it took less than 12 minutes total! . . . (It only seemed like an hour.)
Yep. Not only that, there's also no way they would kill both Luke and Leia in the same movie.
The destruction of the bridge/command section of the Raddus, but sparing Leia, was done for a number of reasons. Among them: 1.) to make it seem as though Kylo has some redemptive value by not pulling the trigger, 2.) to provide a reason for somebody new to take command, and 3.) to allow Leia to finally show that she can use the Force (as was always assumed ever since "there is another").
As to point #2 (to address jye's objection about Ackbar): If the bridge was destroyed, logic dictates that Ackbar would be there. No credible way around that. And to RJ, Ackbar's death was as necessary as Leia's coma in order to introduce a new leader (Holdo). Why a *new* leader instead of an established one? Because we were meant to *not trust* her. Whereas, we *would trust* Ackbar. Poe was meant to not trust her. Poe would trust Ackbar. The chess pieces were moved in that bridge scene to construct a path for central plots moving forward. That's just how the storytelling unfolded. It wasn't done arbitrarily and without reason.
As for point #3: If Rian showed Leia using the Force the way a Jedi would typically demonstrate, it might beg the question of why not use the Force herself during these difficult times leading up to TLJ? So, he probably decided to have her demonstrate Force abilities for the *first* time on screen as a sort of survival instinct. Almost as if the panic and urgency of being at the brink of death sparked her Skywalker-inherited Force powers to save her life. I can see why he'd do it that way, but I still think the execution of the Leia Poppins scene was pretty terrible.
IMO, Rian not killing Leia was absolutely the right call. He also put her in a coma for good reason. And I can also see why he had to have Ackbar replaced by a new character who we were supposed to wonder whether she could be trusted or not.
For some of us who grew up with ROTJ being a pivotal film, Ackbar was more than a mere side character. More than a meme, or a gif. I can totally understand the objection over Ackbar not being given more of a hero's sendoff (I even share that objection on some level). But yeah, I can see the reasons why RJ did what he did with Ackbar/Holdo.