That, right there, is why you're disappointed, I think. Or at least it's one of the major reasons why you're disappointed. You're expecting 7-9 to wrap up with a bow and "defeat evil." What, like how evil was defeated at the end of ROTJ? Except...it wasn't. Not the way they structured Ep. VII (and therefore everything in between VI and VII and all that follows). ONE evil (the Emperor) was defeated, but the Emperor wasn't the sole evil in the galaxy, and the First Order rose from the ashes of the Empire to basically be Empire 2.0. And from the setup we have now...I actually think it is less likely that the end will be all wrapped up with a bow, than that it will be the end of a major chapter and start of a new series of challenges for our heroes. More on that later.
Star Wars is a fairy tale at heart and I might be naive here, but those usually end with "happily ever after". Also, the main point of the sequel trilogy is to be a trilogy. The fact that Nightmare on Elm street 3 didn't end with a bow and final conclusion is not an issue because it wasn't a trilogy that was supposed to be a three-piece act. It was just the third sequel and it wasn't as connected as SW movies were.
So what are our options if it's not a pretty bow and good's triumph over evil?
A Mass Effect-style ending? If you think the negativity towards TLJ is because fans are disappointed that they didn't get their fan-service then wait for the reaction to an ending of that sort.
Or just open-ended? The battle keeps raging on with our Saturday morning cartoon show? How is that a conclusion to a trilogy? And I emphasise that this should be a conclusion because it's planned to be a three-act work from the start. Had they said we're just going to carry a story it would make more sense, but they straight away said it'll be a new trilogy.
I wouldn't mind a kind of bittersweet ending, ROTJ was supposed to end with a tired Luke "walking into the sunset alone" like a spaghetti western hero instead of the ewok disco and I don't think that would've been too bad, even for a fairy tale. Nevertheless it would have been a conclusion too, so Ep 9 does need to be conclusive in a way. Daisy already said she doesn't want to do any more SW films after Ep9, so it kinda needs to end somehow I guess...?
And that's probably the other really big problem with your expectations: you wanted this to be all about Skywalkers. But let me ask you this: what would that actually look like? What kinds of films would those be? I'll get back to that in a minute.
I honestly don't think that's the main issue. I said it many times, the bits I love the most about TFA is everything up until Han Solo shows up plus the confrontation between Rey and Kylo in the end.
Many of the complaints I think people have have to do with mismanagement of expectations, and in large part I lay that at JJ's feet. All of the "mystery box" bull**** is ENTIRELY his fault. The fact that Rian didn't answer the questions JJ posed isn't Rian's fault -- it's JJ's fault for NOT HAVING ANY ******* ANSWERS IN THE FIRST PLACE. How do I know this? Because that's the central tenet of his mystery box approach: the question is more important and more interesting than the answer. It sounds profound, but it's really just hacky. It's a way to create a "hook" that draws people in without ever having any intention of paying it off. So, all the hints and suggestions about Rey's parentage which are ultimately proven to be "Nope. She's a nobody," are a perfect example of this. JJ hits you with a big "OOOOOOH WHAT COULD THE MYSTERY BEEEEEEE?!?!?!?!?!" question, and you spin your wheels for several years, when the answer was ALWAYS "LOL she's a nobody. Thanks for playing!"
Again, I know I'm just one guy, but I said it many times I really don't mind that Rey is nobody, in fact I really really like that idea. Not too fussed about Snoke either. The main issue is that TLJ hardly offers anything else. Take those away and you have the slow space-chase, the casinoplanet (both of which you yourself have issues with), Luke sulking and a final stand and resolution which left many of us wondering regarding motivations and consequences and a movie that doesn't seem to find balance in tone.
I'm pretty sure most people would have no problem with how Rian played those mysteries off if the rest of the movie was more streamlined, focused and gave something genuinely interesting, and most of all well executed.
With regards to your dislike of the mystery box approach, I understand and I agree that it usually leads to more disappointment when it's not played off well. But here's a parallel and I'm gonna be stuck in the world of cooking again. I watch Masterchef Australia, it's an elimination-based cooking show. Every Monday the challenge is (guess what) a mystery box challenge. Contestants get a box full of random ingredients plus they can use a set of staples (sugar, eggs, milk, flour, cream, vinegar) and using at least one ingredient from the mystery box have to cook a dish. And guess who's the winner? The one who can cook the best dish from a set of ingredients that they didn't know about and were not collated based on any specific concept. Not the one who makes an omelette from the staples and puts the thyme leaves on top from the box. On top of that, JJ did have outlines for the story that Rian decided to bin and come up with his own (contradictory to his earlier tweet though). As Mark said in the BTS docu "if it turns out to be great it's only because of him (Rian). But if it's terrible then it's also his fault".
On the whole, though, I liked it. I like that we're moving away from the "Skywalker saga" although, we kinda aren't when you think about it. Ben Solo is, technically, a Skywalker, so we're watching how things play out for him. I think he's a really interesting character, too. Rey is even more interesting to me, and I think she's become more interesting precisely because of how Rian handled JJ's mystery bull**** lead-in. Instead of having it be about the answer to the mystery (which was ultimately unimportant), Rian had it be about what answering that question means for the character.
Again, I'm okay with the decision but there is a difference between character-driven writing and saying that the character wrote the story as an excuse. At the end of the day it's Rian who decided what the character finds important and I think he got it backwards. He first put down the pointer to say this is how I want this character then tried to find a way to tweak the character's mindset to get to his desired point. This is apparent for me when it comes to Luke and his motivations. They are just illogical and all over the place. Rian wanted Luke to be tragic and bitter and tried to reverse engineer how he became that instead of coming up with a plotline that goes from A to B to C based on what we know about them. This is apparent in many places when the movie repeatedly contradicts itself.
Here's another example of character driven writing: Ren offers a place by his side for Rey. What would Rey choose? Considering that she really is a nobody, just been let down badly by a grumpy old guy who was supposed to be a legend and the only person she really had some emotional depth with is Kylo and they just saved each other's asses she may as well do it. She might even have enjoyed the taste of power and success during the fight. Character driven? Yes, because it takes the character's emotions and motivations into consideration. Rian didn't go with it because HE did not want to go with it. It's HIS decision what Rey's decision is. It's HIS decision what's important for Rey. And it's also HIS job to make it clear for everyone in the movie why characters make their choices. Not in the novelization or a Q&A or in an interview.
Waaaaaaaay back when the PT was first announced, and the various EU books were crapping up the Star Wars Universe with the Yuzhan Bio-Borg and such, I had an idea about where the future of the Star Wars galaxy could go. To avoid all the garbage that had accumulated up to that point, I thought you'd really need to just set your story waaaaaay far into the future of the galaxy. The heroes of the OT would be gone, their grandchildren, even, would be gone. The story would focus on entirely new characters who would have no real connection to the past. I thought about that again when they announced TFA. I was REALLY worried about the reliance on the past, and did NOT want to see just another iteration. I accepted it when it happened, because overall I thought they did it well, but I was also really nervous about the films killing off my beloved characters. I got over that, though, and accepted it as just...how things had to go. You can't give the OT heroes a happy ending AND have the same crap happen again 30 years later. It doesn't make sense. You can't really have them be involved as much in the new films either, without also running the risk of diminishing them in some way. Although, that's really how the world works: the old guard gives way to the new. Mostly, I just didn't want 'em to kill Han Solo.
But I accepted it when that's what happened, and I ultimately wasn't that bothered by it. I made peace with it, in large part because I liked the new characters and the direction the story could go. I like the freedom we now have to move beyond just retelling the same Star Wars tale over and over and over again. I should also note that I was a big consumer of the EU stuff up until the Black Fleet Crisis came out, and while I LOVED (and still love!) the Thrawn Trilogy, nothing else ever came remotely close, and all of the other stories seemed to rely upon the heroes being almost frozen in amber. They weren't really allowed to grow or change. They could accumulate experiences, but that accumulation didn't amount to a ton, at least in the books I read. To me, that's the worst possible fate for Star Wars, and it's EXACTLY what I see happening if the films don't really break the old mold the way TLJ did. Now, they still have to remain "Star Wars." They can't just be some other movie franchise with a Star Wars skin, as happened with Star Trek (which is really just Star Wars/generic-space-action-movie with characters named Kirk and Spock wearing primary colored shirts). Star Trek offers a cautionary tale about how NOT to manage a franchise, but I think Disney/LFL has learned that lesson well, and the totality of the stuff they've put out so far suggests that they want to maintain the overall character of the films, while also expanding their focus and style.
I agree with this 1000% (except that I never really cared for the EU). The problem is that this franchise though seems like it's set in a vast galaxy with endless opportunities is simply just limited, because it's a simple fairy tale that you can only tell so many ways and if you try to break the mold a lot it will not work as a Star Wars movie. There's just not much more there and I think this is where my cynicism towards the series comes from and this is why some loudly declare Star Wars to be dead. They realized this too, most of us swallowed TFA as a reboot and wanted to see what happens with TLJ and just realized that you're either stuck in the same old same old or if you try something new (tonally for example) it won't work. As Jay said in Half in the Bag, it's like trying to squeeze a cinematic universe out of Back to the Future. It's three solid fantasy movies and that's it.