Comedy
Here is a trend I wish Hollywood would reverse: if something is funny one time, then 2 or 3 or 4 or 7 times is that much more funny. It isn’t.
This is not just a Star Wars thing. Pretty much all action movies have now adopted this from situation, slapstick and awkward comedies.   A new Spider man bumping his head or falling on his face once or twice can communicate his inexperience in a funny way.   A dozen times is exhausting.
An Asgardian god speaking with some modern English colloquialism might make me chuckle, but when he speaks 100% of the time, even with other gods… and when his sister, who has been locked away for centuries does it… it isn’t funny. It is distracting.
The idea of a fast-infesting little bird/rodent creature on a star ship can be funny (remember, it was funny with Tribbles), and one of those creatures roaring with Chewbacca might be cute. Once. Twice? Three times? Then flying and pressing into a window like a cross between Garfield and Space Balls. It only manages to remind you that this is a movie – cheap entertainment seeking cheap laughs.
There were a lot of cheap laughs in TLJ. There were just a few in Ep 4-6, but most of the humor there was created by relationships, not awkward gags (green milk in the beard?)
The humor was the first thing while I watched it that annoyed me… but now, after thinking about it, it is a lesser evil.
Characters
I will say that unlike some fans, I am not irritated much by new characters with new characteristics.
I think Poe – irritating, prideful, with poorly thought out efforts at humor – is fine. I think Hux – rash, insecure, arrogant, with the tendencies of a “cur” – is fine as well. They are somewhat developed and their exchange at the beginning of the movie feels somewhat realistic to me given their eccentricities.   Would either side have given these two men so much decision making power? No way. However, if I am willing to accept that they did, their stuff doesn’t bug me.
No, it is the introduction of new characters at the expense of established ones that bugs me, and it is the reduction and disintegration of well loved and established ones that exasperates me.
This applies even to characters from Ep 7. Finn was totally wasted in this movie. I wasn’t sure he would amount to much after 7, but 8 finished him as a viable character. Phasma was a complete fail in 7 and 8 did nothing to give her character any relevance.
New characters, like Rose, (I think the actress did fine, though others didn’t; The actress was not the problem) and the purple haired admiral are ridiculous additions. Even if their roles in the movie had carried any value (they did not), they could have been played by established characters.
Examples: The new Admiral sacrifices herself by flying the Calamarian Cruiser into the FO fleet; while Admiral Ackbar dies with a nothing more than a footnote reference. Why not just have Ackbar do it? He is an old fan favorite. Is it because he is male that he cannot save the day?   Maybe there weren’t enough female character heroes in this movie so far. In that case, why not Leia? More on that.
Let me try to exhibit the root problem that I think has been the greatest pain for the fans. It isn’t about somehow trying to recapture a feeling from childhood. Adults loved the originals, too. I have felt it in other movies as an adult. That is cheap. However, I have spent since 1977 seeing certain characteristics of certain characters grow and develop. They have developed defining traits that make them who they are. They are heroes – and complex ones, mostly. We have watched them struggle through great traumas and come out having grown in their character.
So here is the problem. If you are going to change someone’s character, you need to offer a profound reason for it changing. We all know this.
R2
The only character who, in the few seconds that he is on screen, is R2D2… the one scene with Luke was one of two scenes of great relationship that indicated that the director had some connection to the original universe.  Beyond this scene, though, R2 had no real role in this movie.  I know we now have BB8 to play the role of R2 (as seen in Ep 1-3), but this one scene showed how well R2 could have been used.  Speaking of not used well…

Chewbacca
So, what makes Chewbacca, Chewbacca?
Devotion to Han, short tempered, barely more than an animal, powerful, scary to enemies but fierce against enemies.
Nope. He is a purely comic relief character and has no other role. He doesn’t eat animals alive or at least raw, he plucks, prepares and cooks them carefully but also feels bad about it.  He regrets his decision not to go vegan.

Leia
What makes Leia, Leia?
Utter devotion to her cause and her people; a killer instinct and a sharp tongue. Her strength comes not from the power of being a Jedi, but from her leadership and heart.
Nope. She lets others die for her. She celebrates casually after the death of nearly her entire movement. She has some kind of incredible, never before seen Jedi power that saves her – but she only saves herself and not the rest of her officers.   No clever words, so grieving of Han. Very little of the Leia we know.
Yoda is closer than in Ep 1-3, but still too flippant for my tastes. Not enough to complain about by itself. But the real problem is how he interacts with Luke.

Luke
By far, Luke is the biggest problem of this kind.
What makes Luke, Luke?
Now first, I don’t mind at all these characters changing over time and with proper life experiences.   In fact, I liked a few of the changes to Luke when I was able to interpret them as the effects of being friends with Han Solo for 3 decades (the shoulder brush was the best example of this)…
The throwing of his father’s lightsaber over his shoulder was actually my first warning moment in the movie. The treatment of Luke on the island – drinking the green milk, fishing with a hundred foot spear – the whole simpering silly grumpiness just doesn’t work. A little of it might have felt like the introduction of Yoda… but just a little.
But this wasn’t the actual problem.
Luke is an even more simple character than the others since we saw his strongest traits grow only stronger in the years we knew him from Ep 4-6.
Steadfast faith.
He believes in people.
He believed in Obi Wan though he barely knew him.
He kept believing in Han longer than anyone else.
He listened to Obi Wan in the cockpit of the X-Wing.
He believed in his friends enough to risk everything to save them.
And most importantly of all, even though Yoda didn’t believe in any potential for Vader – he seemed to believe that Luke failing to defeat Vader would doom everyone. Obi Wan was very clear about believing that Vader was irredeemable (“more machine now than man”). None of that mattered to Luke. He believed. IN FACT, it seems apparent that ceasing to believe that Vader could be redeemed would have meant a fall to the Dark Side for Luke!
Nope. Now, he begins to suspect that a student – his own nephew – has some Dark Side in him – more than he had thought… and his first thought isn’t “I can help him.” “I can sense the conflict” or anything based on having been a part of the redemption of Darth Vader… nope. First thought? “Light my saber and murder him.”
To say nothing of the idea that he abandons his friends when they need him – which leads to the death of Han Solo (I guess he owes Han 3 now?).
It is no wonder that Mark Hamill referred to this Luke with “He’s not my Luke Skywalker” https://www.youtube.com/watch?v=9fWELFcwpNs
What he is, is not the Luke Skywalker of Star Wars history.
Next, conclusions…