Sure Luke was whiny. Sure Luke was impatient. Sure Luke was naive and reckless. Sure Luke was scared..... and then over the course of three films we all watched as those edges were ground off by the trials and tribulations that he had to go through.
At the end of ROTJ our Luke is now a well rounded, mature individual confident in his abilities and mindful of his limitations. He's faced his demons and won the battle against his fears. His steadfast love, loyalty and respect for his friends and remaining family is unbreachable and has seen him win through to the end. He finally stands before us as a fully fledged Jedi, saviour of the galaxy and hero of the hour.
And then along comes this Rian guy who proceeds to pick out some of the elements that make up Lukes character from different time periods of his character arc... he puts them all in a hat, jumbles them up and then spews them at the screen with a total disregard for any thematic context or coherent character continuity.
He definitely grows throughout the trilogy and that reaches its climax in ROTJ but he's still imperfect up until the end as his fight with Vader shows. Who's to say that he becomes this infallible person after the end of the trilogy and that he'd never make mistake or never get angry and disappointed.
TLJ shows that he isn't perfect and still has flaws. They didn't disappear entirely, there was just something bigger there at the time, like how it often is for people. It eventually got to him when it involved his own family/friends and because it was his own mistake. With some help though, he found his way back again.
I can understand not wanting to see Luke become just another flawed person as he's a paragon at the end of the original trilogy. However, I think what happens with him in this movie is pretty in character based off what we know. If anything, I think it makes him an even more appealing character because he's now been hit with more hardships in his life but has found the strength to move forward again. He's still that amazing person we see at the end of the ROTJ but just a little more human.
This is also how I felt about Han in The Force Awakens who has a very similar arc in that movie. Han wasn't able to cope with what happened to Ben and it caused him to revert to his smuggling life and separate from Leia. Yet, he finds hope again to try and fight for his son and reunite with the love of his life.
can someone explain the hole of negative energy Rey explored and why nothing came of it?
Not really sure if they had enough information in the film to really discern anything about that hole. It would be something interesting to tackle in the next film if they bring back any concepts from this into that.
The most we can see is that there's something there and it could cause a Jedi to lose themselves. Rey's own purity, I guess?, allowed her to interact with it head on remain unphased. Symbolical, it's 100% fear but it'd be neat if there was actually something there.
I've come around to appreciating the overall character arcs in the movie, for the most part, after spending some time reading opinions on the Star Wars subreddit. I still find everything in the movie that doesn't revolve around Luke, Rey, Kylo, and Snoke to be a complete mess.
Yeah, it also doesn't help that none of the other characters really had a direction they could go with coming from TFA. Their characterizations weren't, IMO, strong enough to help figure that out. They tried a bit in this but it kinda just doesn't work. Poe was too cliche in this film. Finn doesn't have anything he wants to work towards or fight for. The characters they introduced in this aren't bad but sabotaged by some of the hollywood cliches and likely, executive meddling.