Phasma : Phasma should have been TR-8R in TFA, dueling Finn with the electric baton. Instead she was a huge wasted opportunity, mostly because the script was written long before Christie came in, and the marketing hyped her character way more than they should have. It's the Boba Fett syndrome though, people liked her because she looked cool but she really doesn't do much. She at least does more in TLJ, though it still feels like it's a lot of hype for not much in the end. Glad she got her ass kicked, but I have a feeling we may see her again.
Slicer/DJ/Del Toro : Felt weird. Casting choice was odd. His mannerisms also. In the end, this whole subplot is unclear because they originally went to hire ANOTHER slicer and somehow ended up finding the best one ever randomly. Who also betrayed them but it's not certain whether that was his plan all along or not. So yeah, this subplot was unnecessary, its only payoff was to bring Finn and Phasma face to face but could have been handled better.
Finn/Rose : I didn't mind the love story, Rose was not as annoying as I anticipated. Her story arc was satisfying but could have done without the casino part as mentionned above. I really thought Finn was going to sacrifice himself in the end on Crait. Glad he's not dead, I like him.
Holdo : I didn't care for the pink curly hair, but the character was pretty interesting, and the politics/munity stuff was well done. Her epic sacrifice and the related scene redeemed the pink hair I thought.
Cat-horse mounts : I thought they were cute. Not sure why you got so angry over cute animals. The point is to heavy-handedly show the Resistance is the good guys because they care about nature and the greedy corporate casino players and the evil empire don't care about animals. It's not subtle one bit, but no one ever accused Star Wars of being subtle, the same thing happened with the Ewoks.
Rich vs Poor : I thought DJ's point about how some iron mongers got rich by selling weapons to the Empire but ALSO to the Rebel Alliance/Resistance was a fine point to make this usually so black and white conflict look a bit more grey. In the same way I liked how Cassan assassinated someone in cold blood in Rogue One, because it shows you can't be a Rebel Alliance blowing factories up, stealing things and killing imperial soldiers without doing shady things and looking like terrorists most of the time.
Snoke : On this point, I disagree with you because this scene was handled and explained very properly I thought. Obviously Snoke is very confident, too much, and he thinks he cannot be betrayed by Kylo Ren because he can read his mind. That's why Kylo Ren acts this scene as he does, because everything Snoke senses is true. He is facing Rey and turning his saber towards her, and Snoke says he can feel him thinking about doing it, because he is turning the -other- saber... then preparing to kill his enemy, because he is thinking of it in that way, except the enemy is Snoke in this moment. Obviously I don't have to explain the scene, you saw it yourself, but really the whole "I can read his every thought so he cannot surprise me" was well-handled because it was turned on its head and I thought it worked great. Everyone was very surprised in the theater when it happened, and it was a really bold move.
Praetorian Guards : The Emperor's Royal Guards looked very badass. Never moved an inch. The Praetorian Guards had an extended fight scene and proved a challenge to two of the most powerful Force users in the saga. I'd say they did the job.