The sequel trilogy has been a letdown for me. I'll keep this brief as I could go into explicit details on this, but generally speaking, Disney had the Star Wars universe at its disposal and the best they could do was provide us with A New Hope retread and a follow-up that spins its narrative wheels.
I'm one of the few that wasn't fond of TFA, even after my first viewing. Once they revealed Starkiller Base, I turned to my wife, who looked at me, and we both said, "This is a remake of A New Hope."
Yes, I understand the corporate move Disney played here. You had to "reintroduce" Star Wars to the current fanbase and give it a proper introduction to the next generation of fans. While it worked financially, I found it uninspiring.
My biggest issue with TFA is this: If you're going to basically remake ANH, then remake ANH and don't call it Episode VII. A continuation should not follow a nearly identical story line from a distant predecessor. I've seen this story before and I need something new, especially in a Star Wars movie. The prior six movies did this well, even if some of the prequel stories weren't as exciting. Those movies at least expanded the universe. TFA adds new characters, but doesn't do anything worthwhile with them. Rey dreams of leaving Jakku, joins the Resistance and they deal a major blow to the First Order. Seen it before.
I'm not an EU reader, but a more compelling setup to kick off a new trilogy would be Luke and a promising apprentice investigating a distress call on a distant planet only to learn that an army of Sith (who don't abide by the rule of two) have overtaken an entire system of planets and are setting their sights on the Rebellion's system. Something different with the opportunity for new characters and our familiar ones to unite to stop a growing threat.
Or maybe you set TFA in a world where the Rebellion rules the galaxy and the threat of a takeover lies within their own ranks. A new Empire and a new Rebellion just didn't do it for me, especially when the window was 30 years. The First Order rose from the ashes of the Empire and has more power and a massive fleet? Seems really unlikely. For me, the most exciting stuff in TFA took place in Rey's vision.
The Last Jedi's first mistake was setting the movie right after TFA. They needed a time gap to establish a better setup. Watching TFA and TLJ back to back makes you realize the emotional rollercoaster the Resistance went on in the span of 72 hours or so (spitballin' that duration). From destroying Starkiller Base to having their entire fleet reduced to about 30 people must have been jarring. Though they seemed pretty optimistic at the end of the movie. Sigh.
I could go on, but I've already gone past being brief. I'll sum it up this way: I don't HATE the sequel trilogy. I'm merely underwhelmed by it. And that's unfortunate given how content rich the Star Wars universe is.