This was simply a bad movie. TFA was derivative, but introduced some likable new characters to the franchise. TLJ was just a mess.
1) Plot: Slow speed chase of Empire fleet trying to catch Rebel corvette to eradicate last remnants of resistance. SLOW. SPEED. CHASE. Really? The empire with all their technical wizardry have no solution to catch the sea cow of spaceships? What happened to the Tie Fighters? They couldn't be scrambled to knock out shields, run interference? Furthermore, why didn't the resistance just hyperspace over to their salty safety planet and preserve their fleet, considering that the First Order would have tracked them either way? This moronic plot device sets up even dumber subplots.
2) Subplot #1: leave the main ship to streak across the galaxy to find a hacker at a casino who will be identified by. a... broach. Streak back to Snoke's ship, sneak aboard and knock out a hyperspace tracker. If I pitched this to any of you guys you would have been like - "WTF? That's stupid". Yes it is. The super cheesy CGI in the casino only amplified its awfulness.
3) Subplot #2: Poe mutinies. Why? Because he does not know the plan to launch the escape shuttles and send them to a fortified outpost. Why isn't this disclosed? Why doesn't the inept Rebel leadership simply share this with one of the heroes of their cause? We wouldn't have to waste an hour of the movie on inane misadventures.
4) Snoke. Let's set up this hackneyed pantomime villain, make him the genius that reconstitutes the tattered empire into the dominant First Order, give him godly force powers.... and then slay him in 3 seconds without ever explaining, who he was, where he came from, or why we should care.
5) Luke Skywalker - If you are going to kill him off anyway, why not let him go out in a blaze of glory? Astral projection? That's the best you got? This is the guy who killed a Rancor, faced down the emperor, blew up a death star, redeemed Darth Vader and you make him a prop? How epic would one last fight between he and the Empire have been - where all the powers Luke learned and cultivated could be fully unleashed? His death was the definition of anti-climax.
BTW, Hollywood cannot comprehend that there are actual heroes in the universe that recognize evil for what it is and reject it. Hollywood loves moral relativism, anti-heroes, internal conflict - (at least within men - women, of course, are vessels of pure light). I am okay with Luke questioning his faith - but he was intimately aware, like no other person in the galaxy, with what the dark side creates: slavery and death. That he, with that knowledge would de-enlist himself from the battle against the Dark side is a betrayal of the character as we know him. That the person who redeemed Darth Vader would be cowed by the prospect of redeeming Kylo is just illogical.
6) Leia - Force bubble. Oh dear. Can we still call Star Wars science fiction? Shouldn't there be some understanding of science and what happens to the human body when exposed to -450F degrees in space? Also, Carrie Fisher could barely emote with that scotch tape face-lift and botox. I found her off putting in every scene.
7) Rey - I like Daisy Ridley but she doesn't have much to work with. She is a completely one dimensional character with zero weaknesses.

Deus Ex Machinas Everywhere: We need a hacker. Oops we're in prison... coincidentally with a hacker....who later rescues us...and gets us on board Snoke's ship... then double-crosses us....now we're going to be executed... but Snoke's ship is serendipitously damaged before they can kill us....but the hangar bay is in ruins with ships exploding all around us... oh dear what shall we do....wait there is perfectly intact imperial shuttle over there amidst the fiery rubble... and it's right by the exit door - huzzah!
We are in a slow speed chase bleeding fuel and watching the last remnants of the resistance get picked off one by one... that's cool cuz we know there is a salty safety planet only a few parsecs away with a giant impregnable door... "Ha ha" says the empire "we have a mini-death star door destroying cannon...so there"...yes, but the resistance has crystal kitties that show them a backdoor....but it's blocked by tons of boulders....enter Super Rey! huzzah!
9) Light saber battles. What happened with Snoke''s henchman? The Light-saber is arguably the coolest weapon ever imagined. The duels are probably the most exciting parts of the movies. But this was so feebly choreographed that I just wanted it to be over. Where were the gymnastics? Environmental force attacks, etc? It was just so perfunctory and the costumes on the henchmen looked like something from Flash Gordon - not menacing like the Sith priests in the OT.
10) CGI - How is it that Gollum 17 years ago looked more realistic than Snoke? All of the CGI in the casino, especially the floppy eared horses, was terribad. Disney has billions. How does this happen?
Anyway, I've wasted enough time. Has our society become so dumbed down that the obvious absurdities in movies like this are no longer apparent? We live in a post Game of Thrones world. These writers need to trust that audiences are a little more sophisticated now and stop pandering to the CBS sitcom crowd. Plots need to make sense.