I beat the main game yesterday. It took a while since I like taking things slowly when I play through Pokemon games, and this was no exception. Haven't had a lot of time to play either due to various things in real life stealing my time, but that's a different story. I haven't read through this thread in full yet, so there's a big chance I'm going to repeat some things that others have already said. This contains spoilers, so if you haven't beaten the game yet, don't read, go back and play instead! Though I guess most people have beaten the game at this point. Wall of text below.
To start with, let me say that I liked the game. However, I can already now say that these games are not going to be my new top favorites, though I still think they are good and I am sure they will end up somewhere in my top 5. The post-game will be the judge as for their exact placement. I have some hopes and some fears, will have to see what turns out to be the case and what doesn't.
I played Moon, and I have to say that I really like the version differences when it comes to time. I pretty much never played OR/AS at night, and I think the true night began too late in Gen 6. Playing this game where it was night during the day was really cool since I mostly play during the day.
I like the regional dex, it is large and varied which is always good. The story and characters were good, I liked them. I love the new Pokemon as always, they have awesome designs. I'm pretty sure I have seen all of the regular ones so far, but I'm unsure if I have seen all Ultra Beasts and legendaries, so there might be a few surprises left. I like the idea of Alolan forms too, I hope they keep it for future games/generations and introduce more of them, either more Alolan forms for a potential Sun/Moon follow-up or other kinds of variations for future regions. Perhaps they can give the non-Kanto Pokemon a chance too. Haven't used any of them yet, but my favorite Alolan forms in terms of design are Raichu, Golem, Marowak and Ninetales.
That said, I am not a fan of the small number of new Pokemon. While they have great designs, I like it better when there are many new Pokemon. I feel a bit spoiled by Gen 1-5, especially Gen 5. I think 100 should be the bare minimum for how many new Pokemon there are each generation, though I can completely understand why they are adding less new Pokemon when you look at it from an economical perspective. There were also many new single-stage Pokemon this time around, ones that doesn't have any evolutions or pre-evolutions. Counted and got the total to 14 (not including legendaries). That is as many as were introduced in Unova, which had almost twice the number of total new Pokemon. In comparison, Kalos only had 5. I'm not saying it is good or bad, just an observation.
I love how they dared to try some new things, like removing the HMs and adding the Poke Rider instead. Feels like something they should have done long ago. The same goes for the Trials being there instead of the Gyms, I thought it worked well. They finally tried something new. Doesn't mean that the Gyms can never return in the future, but at least they tried something different one time. I am also a big fan of the graphical updates, the games feel much more polished and serious when it comes to the graphics compared to Gen 6. Getting rid of the chibi models was a good thing since it helps the games feel more serious and mature. I played Alpha Sapphire a little alongside Moon, and it felt like a completely different game. The difference is really big. Most of the other new features in the games are really cool as well, though I haven't tried all of them in full yet.
My in-game team consisted of Primarina, Salazzle, Tsareena, Mudsdale, Toucannon and Kommo-o. I decided early on that I wanted to try using new Pokemon only, and this became the result. I also wanted to have a FWG core, as well as a balanced team in general when it came to types. Plus the usual, a starter, a surfer, a flier and a Fairy-type. But it turns out I didn't need the surfer or the flier! This will ease up team building on Sun when I play through it. My team worked, though with the exception of Salazzle and to an extent Kommo-o, they were quite slow. All except for these two had a base speed below 80, which made a surprisingly big difference. I found myself getting outrun by opponents more often than not, including wild Pokemon like Raticate, Dugtrio, and Golbat. Speaking of Golbat, playing through Moon made it my third least favorite Pokemon overall, but that's for another discussion. As for the availability of my team, it was quite good, Kommo-o was available a bit late but that's the only thing. I let all members of the team hold a Z-Crystal, but I only used Z-moves against important trainers, as well as against wild Golbat. When I play through Sun later on, I will probably not only use new Pokemon once more, will try to mix up things a bit more. I have a few ideas and will see what I decide to go with.
Unfortunately, not everything about the games is good, and that's why they are not my new favorites. I don't like how almost everything about the games were revealed before their official release. A majority of the new Pokemon, the Ultra Beasts, the Alola Forms as well as most features and story-related things were shown beforehand. This made things a whole lot less surprising. I managed to avoid most of the leaks from the demo datamining and the full game leak, but got spoiled on a few things from them too. Someone might be thinking: "Well, if you don't want to see the new things from the games, don't look at all the pre-release material." And that's a completely valid and fair point. It is, more or less, my own fault for spoiling myself. For the next main series release, and for future generations, I am definitely going to be more "blind" before going into the games. Thinking back, that is another of the million things I liked about B/W, I knew next to nothing about the games before I started playing them which made it even more of a completely new experience. In comparison, I looked at too much things from X/Y and S/M before I started playing them. That's not to say the games haven't contained surprises because they surely have, but I feel like I have known too much beforehand.
Like with Gen 6, I'm not a fan of how they have removed many useful features from the previous generation. So far, I'm missing O-Powers, Hordes, Super Training, the red "X" and the DexNav. Perhaps other things too which I can't think about right now or haven't discovered the absence of yet. Online and communication features also feel a lot less convenient, I think I prefer the PSS over the Festival Plaza when it comes to communication. Admittedly I haven't used the communication features that much yet, so I might be wrong. I should have expected them to remove several features from Gen 6 since that's what Gen 6 did with many features from Gen 5... but still, it stings. I need to learn to live with it.
Then there's the fan pandering to Kanto fans. Once again, Kanto gets the spotlight, and kind of steals it (or at least parts of it) from Alola. There are many Kanto Pokemon in the game, at some parts in the beginning it felt like I ran into nothing but Kanto Pokemon. Now I don't know exactly how many there are in the regional dex compared to the other regions so I might be wrong, but that's what it felt like at least. And just as I thought would be the case, Alola forms are limited to Kanto Pokemon. But that isn't all bad since I think Kanto has the most boring and uninteresting Pokemon, so they are the most in need of being spiced up. And yet, even with all of this, I can still forgive Game Freak. Despite all the fan pandering during this and last generation, they still haven't crossed the line. Maybe I'm getting soft, but that's how I feel. I do hope they stop with it now though, there's no reason to continue anymore now that the 20th anniversary is over.
I also felt that the level curve, or rather the difficulty curve in the games, was rather unbalanced. At one point I'm doing just fine and then I'm suddenly underleveled? There were a few big jumps, first between Islands 2 and 3, then 3 and 4, then to the Pokemon League and then finally to the post-game. I haven't found any good ways to rebattle trainers or level grind either, apart from beating the highest-leveled wild Pokemon you have access to, so this is kind of a problem. Plus, most trainers in the game only have 1 or 2 Pokemon. Some people might argue that this makes the games easier, but I'd say the opposite. It makes the games harder since that means you get less Exp, more or less forcing you to grind more against wild Pokemon if you want to level up some more. Now I played with the Exp. Share turned off during the majority of the game (turned it on just to grind before taking on the Elite Four), so I'm guessing the games are a bit easier and more balanced (relatively speaking) with the Exp. Share turned on. It feels like Exp. Share Off is the "Hard Mode" this time around while Exp. Share On is either "Normal" or "Easy" Mode (I don't know as I haven't tried it myself). Unpopular opinion perhaps, but I don't like this. I want my Pokemon games to be easy unless I tell them to be hard.
Overall, the game felt like a new X/Y. Which is really strange when I think about it considering how X/Y were very "regular" Pokemon games while S/M are daring and surprising, trying new things in many instances. But there are three things that give me this feeling: the low number of new Pokemon, the fan pandering to Kanto fans and the removal of many useful features from the previous generation. Three things that X/Y also had or did. I had hoped for a new B/W and I got a new X/Y instead. Which isn't too bad since I like X/Y, but this isn't exactly what I wanted the new generation to be. It feels like Game Freak have done the same thing twice in a row, which I don't think has ever happened before.
So those are my thoughts so far, except for potential things I have forgotten. As said, I liked the game, not my top favorite but the main game was still a lot of fun. Like most Pokemon games have been. Now I'm going to see what the post-game has to offer. Might come back with a new post once I'm done with that, depending on how long it takes and if this thread is still around by then, we'll see.