My two Republic Credits on the matter:
TLJ Is a movie that has a few good moments which get buried under all the bad, the meh and the nonsensical moments.
I thought that Mark Hamill did a good job playing his character, despite not liking this version of Luke. I like Luke breaking away from the Jedi Paragon he is always portrayed as and instead going for a more grey-aligned stance. Hes kinda like a Jolee Bindo with less sarcasm, and I like that. I probably would have enjoyed these scenes more if it wasnt for Mary Rey Sue.
Canto Bight was...interesting. Its another one of those gathering places for "the worst scum in the galaxy", but this one at least gathers a different type of scum. The corporate kind. It also tries to introduce some nuance into it with the whole arms merchant bit profiting both from the First Order and the Rebellion. Its not a lot, but it is there. On the other hand, its the most ill-fitting piece in a movie which was already kinda struggling to remain coherent.
Snoke is annoying because he is a waste of time. His only purpose in the story thus far was "he is the reason Kylo Ren fell to the Dark Side", but Kylo could have easily fallen to the Dark Side all by his lonesome, without the need of wasting time with this lame Emperor Vista Version. All of that screentime could have been used for a more worthwhile purpose. Killing him in this movie just shows that no one involved in Nu Star Wars even knows how to construct a story.
Mary Rey Sue is boring, and its to the movies detriment to focus so much on her. If there was any doubt that she is a Mary Sue, Yoda put them to rest with his short appearance (
) in this movie, which would have been better IMO had they just used the original CG technique. Mary Rey Sue has no motivation, because her only motivation is to be a Jedi and, for all intents and purposes, she already is a Jedi without any effort invested (she definetly didnt train). She cant grow as a Jedi either because she essentially "already knows everything she needs" (paraphrasing Yoda here). The only thing she might have learned was, as the movie puts it, failure. But she doesnt, because she simply doesnt fail, ever. She didnt fail to turn Kylo Ren, Kylo Ren was the one who failed. She didnt fail in her training, it was Luke who failed as a Master.
And then you have the laughably awful bits. A picture says more than a thousand words, so:
Honestly, even if its a bit vague how the force works, I think there were many other ways in which you can do the "Force Ex Machina" thing, where Leia uses the Force instinctively to save herself. They still would have been kinda bullshit, but I dont think it would have looked as awful as this scene did at least.
So like I said, her plan failed because she didn't inform anyone but her closest and in turn it ended in absolute failure. And in the end the plan was doomed to fail anyway.
The way I see it, the plan wasnt doomed to fail anyway, least not in the context of the movie. What actually doomed Holdo's plan was keeping Poe in the dark. She actually could have prevented its failure had she just informed Poe of the plan, then Poe wouldnt have gotten desperate and OK'd the whole "disable the tracker device" plan, which is what took Finn and Rose to Canto Bight to find the decoder (whatever his name is), who in turn is responsible for blowing the lid on the rebels plan by telling them about the stealthed transports. Had she just told Poe, then there is no unauthorized mission, no decoder getting caught and cutting a deal, and then the plan would have worked with the transports managing to slip away undetected.
But, the way in which it was doomed to fail anyway is due to this obsession with "subverting expectations" the movie keeps doing, which got old real fast. Even M. Night Shyamalan was telling them to knock it off.