How the heck can ANYONE hate gen 7? They weren't perfect perhaps, but putting them amongst the worst in the franchise is complete and utter horseshit. In fact, I firmly believe the opposite: Sun and Moon are tied with Black and White 2 for my favorite mainline Pokemon games, with the mediocre postgame being the only thing holding them back from being better, because aside from that, they did every other conceivable thing right:
Not to disagree with the points you brought up, but I thought I'd give some reasoning for why I consider Sun and Moon absolute bottom-tier among the Pokémon games. In short, I find the presentation lacking, and what could have been really good games for reasons you stated, are marred by some highly questionable design choices. That's the gist of it, now let's dive into the details:
For a start, I think it's fitting to consider the beginning of the games. While a mandatory tutorial has been a staple of Pokémon games for ages, Sun/Moon takes the cake and runs with it. The amount of hand-holding in the early-game is excruciating. I haven't sat with a stopwatch to measure it, but it really takes a couple hours' worth of playtime before it feels like you can go explore anything. There are long, unskippable dialogues and cutscenes everywhere in the beginning of the game, which really hurts replayability. It takes forever to get to the point where you're left to your own devices. Until you battle Ilima for the first time, you're always told to follow a specific character to a specific location, following a specific route, where there will be more cutscenes. Only then does Route 2 open up and you're free to go to Verdant Cavern at your own pace. Of course, once you get there, there are more cutscenes. Granted, the story is better than what we've seen in Pokémon games so far, but it's presented in such a tedious way. Lots of mandatory dialogue, lots of cutscenes you can neither skip nor speed up.
And that really sets the tone for the entire game. It feels like the entire overworld gameplay of Sun/Moon consists of "go to the spot marked with a flag on the minimap, where there will be a cutscene and maybe a battle". There are no traditional dungeons to explore or overworld puzzles to figure out, it's always "Go to flag, then cutscene". It doesn't feel like you're exploring Alola, you're given a guided tour. And it's not like you can branch off the path much; if you even find a side area, it's usually blocked off with a very immersion-breaking fade-to-black roadblock. "Oh no, you didn't go to the flag, we will have to reset the area so you face the right direction. There, now go to the flag!"
I don't think the region itself is particularly engaging either. You're usually following roads with the sea on one side and cliffs on the other. There is one way forward, and one way back where you came. Branches in the path are either blocked off until later (That obnoxious Stoutland guy, Haina Desert, Route 11) or contain very small side areas (Seaward Cave, Ten Carat Hill). As mentioned before, the region hardly has dungeons to speak of. The trial sites are very small, the caves are linear, the forests all but absent, and even with two evil teams we still don't have a labyrinthine lair to explore. The four Tapus each have a temple, all of which contain one
Strength Machamp Shove puzzle, that's it. All in all, the region feels small and cramped, not particularly helped by the fixed camera angles (which, to be fair, is probably a hardware restriction. Then again, Super Mario 64 DS had a free camera in a 3D environment, so eh).
And this is just the broad strokes, the setting and principal concept of the game. Other, minor design decisions really made me question the competence of the game director. For instance, greenlighting the Rotom Dex. Or the godawful Pokémon distribution, where the Rattata, Yungoos and Wingull families make up a combined total of 60 % of the wild Pokémon encounters in several routes all up to the postgame areas of Poni Island, while the new and interesting Pokémon are near impossible to find without a guide. Unless you knew beforehand where to find Bruxish, Mareanie or Dhelmise, you sure as heck weren't going to find one through normal play. And even when you know where to find them, it's still a repetitive, grinding slog to obtain them. Speaking of repetitive and grinding, somebody had the good idea to make key battles more challenging (a decision I wholeheartedly applaud), but many of those challenging battles are preceded by cutscenes you have to watch every time you attempt the battle again. The worst offenders are Kiawe's trial (requiring you to climb the volcano and do the same photo riddle every time) and Po Town Guzma (where you have to walk from the Route 16 Pokémon Center up to and through all of Po Town [including 12 fade-to-black loading "screens", I counted] plus a lengthy Guzma speech before every rematch). Those are legit difficult battles an inexperienced player might attempt half a dozen times or more, but every attempt has to include three minutes of unnecessary fluff before you can get to the battle itself.
PokéRide was a nice mechanic in theory, but its implementation was somewhat iffy. Consider for instance Machamp Shove, which I think is used a whooping total of five times throughout the entire game, four of which are in the Tapu temples
and all of which only have to be done once. At that point, one might as well not make the puzzles dependent on Machamp and just ditch that Ride Pokémon altogether. Mudsdale Gallop is even worse. You use it to cross rocky fields, none of which are accessible until the moment you get Mudsdale. The fields and Mudsdale both have the sole purpose of justifying each other. There is no challenge in that mechanic, no skill, no element of chance, no lore, no "how do I get past this?" riddle. It's all just "remember to mount Mudsdale before walking here". Mudsdale is two button clicks away from the moment you see the first rocky field. Worst thing is, they put a roadblock right before that, so even if you sequence break you can't get to the obstacle and wonder how to get across it. I don't know what to call that, but it's certainly not competent design.
But I could go on and on about details (and I believe I already have), it's not the main point. All in all, what really killed the enjoyment of Sun/Moon for me was how it appeared to refuse to take after previous games. How so many of its aspects had been done better already, how many areas it failed to improve on, and previous successes it failed to embrace. It didn't have XY's or Platinum's fantastic Pokémon selection, the snappy early-game of RBY or GSC, the DexNav of ORAS, BW's great level of polish, the sprawling landscapes of Kalos, the wilderness of Sinnoh or any of the postgame facilities or daily battles/events of multiple earlier games. The popular Mega Evolution mechanic was all but ditched, there were no Secret Bases, Festival Plaza was a strange and barely coherent mess compared to the smooth and convenient PSS, there were no trainer rematches at all, and I could go on and on. It's not that these aspects in themselves make the games worse, it's how it all seems to convey a refusal to learn from past mistakes (or successes) and how progress is held back for the sake of doing things differently. In short, it reeks of poor direction.
In conclusion, Sun and Moon either felt rushed or stubbornly different for differences' sake. It had some great highlights, you mentioned some and there are others as well, but some really questionable lows too. And in many cases it felt obvious that these lows could have been done better, either by putting in a tad more work (the Pokémon distribution for instance - it would not have taken a day to tone down the rodents and seagulls and fill the routes with more interesting 'mons) or simply by doing what had already been done well before (
anything on the bottom screen). I applaud the games for ditching the HMs, giving us more fleshed out characters, making pretty environments, and the battles are more interesting than ever, but there are certain aspects of Sun and Moon that aren't just bad, they are worse than what Game Freak had already presented in previous titles. The old adage about Game Freak - One step forward, a few stumbling steps to the side, one step back - is nowhere clearer than in the Gen VII titles.