My last post itt, take it as you will:
There will be change in Pokemon. That's a fact. Unless you've been living under a rock or have genuinely never played Pokemon before, this is something to be expected. Game Freak removes and adds features every single generation. The Poketch? Removed. Xtransciever? Removed. Vs. Seeker? Removed. Battle Frontier? Removed. Pokemon following you in HGSS? Removed. Difficulty altering modes after B2W2? Removed. I can honestly go on and on about this but I will be honest and say that a lot of the reason you're facing some pushback in this thread is because this is nothing new on Game Freak's part, and a lot of people know this. They will always make some additions every generation that's polarized amongst fans. In Gen VI, it was Mega Evolution. This generation, it's Alola forms. No matter what Game Freak does, they're never going to please everybody. They can most certainly try, and that's their general aim, but it will never happen because there will be someone mad enough that the experience isn't tailored enough specifically for them.
Secondly, you can develop whatever opinion you want. If, ultimately, you feel that the games aren't a fit for you based on what you've seen so far, so be it. I disagree with the premature judgment, but hey, that's your thoughts on it and if the last four pages of this thread have been of any indication, you're probably not going to change your mind on that, and chances are you're not going to change the mind of anybody you're replying to. I don't think that's your aim, as you've stated earlier you're just here to post your opinion, and that's fine. I do think however, that this has become rather one-sided and very repetitive; you keep saying that you feel that the recent generation is losing its nostalgia because of the removal of Gyms among other new additions, while others are stating to you that this isn't the case; that Pokemon has and always will be what it is at its core: catching, battling, trading, and communicating. Nothing more, nothing less. How Game Freak does that is ultimately up to them. You may not be satisfied with how they go about with these core functions, but as long as they keep them intact, it will always be Pokemon as a lot of people know it to be.
That being said, if you feel you are going to be unhappy with your experiences with the games, then do cancel your pre-orders and skip out on this generation. A lot of people in this thread disagree with you that the removal of Gyms is removing a component that would be sending the games in a death spiral, but hey, opinions are opinions and as I said, not everyone is going to be pleased with a specific generation of games. That's just how it is.
On another note: difficulty in Pokemon games are hardly going to be a thing. As much as some veteran players (even myself) would want it to be so, the fact of the matter is that even if you see that more adults play Pokemon, the general demographic and aim for Pokemon is for children. These games are developed so that it would be easy and simple for children as well as those who've never played Pokemon before to get into; making the games difficult would most likely turn them off and away from it.
tl;dr: We're all here to enjoy the Pokemon games for various reasons. Some of those reasons are more for battling, some of them care more for plot, some of them care for post-game, some more for trading and breeding. What makes Pokemon such a fulfilling experience in many people's eyes is that these core aspects of the games don't seem to be compromised. In fact, they're made easier, if anything else. It's possibly likely that Super Training will make a return, Hyper Training is making getting into battling a breeze, breeding is ridiculously easy with Gen VI and will likely be easy in Gen VII.
The point of all of this is that Gyms, while a staple in the series, are only a tiny part of what makes Pokemon what it is. And I know you're going to respond to this with "well why not replace Pokemon with nets lol", in which case I'll respond that Pokeballs are universal. They can fit anywhere, in any region, in any environment without looking out of place. Everyone knows what a Pokeball is, they're a standard method of capturing Pokemon and Pokeballs are a trainers' trustworthy tool to capture Pokemon to fill up the Pokedex. Gyms however, as much of a staple as they are, they can very well be removed because, as this generation proved, Gyms are not the only way one can be recognized as Champion of a specific region. If this point seems silly to you, then I'm not sure what else to say, but it is what it is.
Z-moves and the such are not difficult concepts to learn, in fact, I believe they're explained even in the demo. At any rate, it sucks that you aren't happy with them, and I hope that, if you do plan on getting the games in the end, that you'll be satisfied with your experience and that SM will be a decent game to play through, after all.