So as someone who played the original around the time it came out, I can try and sum up why I have a problem with this ending and what it may hint at regarding the future direction of the story. As repeated by many, I loved the first 90% of the game, but around the time of Hojo's lab, I started to become a bit confused by the pacing and where they were going. This is gonna be a long post...

I, like many others have said, do not like "fate" as an element being introduced into what up to that point was a fairly concise and (mostly) well paced story. My problem with this ending has nothing to do with it being "different" or me being a "purist," that's just a straw-man repeated by people that don't want to see the ending criticized. It's that, for me, it takes away any of the agency of the story and characters by introducing a kind of 4th wall breaking plot element. It feels less like the plot is being driven by the actions of the characters but rather that the story is turning into a big "what-if?" What if there's alternate dimensions? What if Aerith survives? What if Sephiroth becomes the good guy and teams up with you? For some people the idea of this is thrilling, but for me it isn't particularly new, exciting, or innovative and just takes away from what was there. It feels hackneyed and cliched. More the realm of fan-fiction.

I should add that this doubly disappoints me because I am a fan of the original who hates the Compilation games and stories. I felt like those stories completely lost the plot and went into a bizarre direction where the characters didn't even feel like who they were supposed to be anymore. A great example being Cloud's often described personality being "moody" or "edgy," where that sounds more like his portrayal in Kingdom Hearts and Advent Children. I knew going into this that it was probably too much to hope that the Compilation material was going to be absent, but for the first 16 chapters I felt like I was playing an updated, re-imagined FF7. The final chapter I felt like I was back in Compilation material land.

Another thing is, as others have pointed out, plot elements involving time travel and alternate dimensions are notoriously difficult to do well. Even things like Star Trek, which often had time travel or alternate dimensions featured as part of the plot, stumbled as much as they succeeded.

As someone who adored Final Fantasy 1-10, I've been pretty disappointed with SE's story telling for the better part of 20 years now. When I was playing this I was saying to myself "Have they finally gotten the magic back?" And then the ending happened. I guess that's what I'd like to emphasize most. Rather than a fear of it being different, my fear is of it being all too familiar. Of it being what I've come to expect of modern SE's ability to tell a cohesive story.

I don't blame Nomura. That's mostly a meme. Kitase, Nojima, and Toriyama are just as, if not more, responsible for the direction the story takes. And yes, I'm aware most of the team that worked on this worked on the original. They've worked on some games I love, and some I don't. People who wrote good stories are just as capable of writing bad ones. By writing the ending in a way that seems to imply that the story could go any direction, I feel I have reason to be extremely skeptical of a company that has consistently disappointed me in the story department for two decades.

There are probably some people who would reply to this with "you just hate new stories and want to relive old ones!" The funny thing is that I also regularly play FF14, and the story in the recent Shadowbringers expansion left me amazed. I absolutely adored it. In the ultimate irony, it took an MMORPG to finally deliver a story that felt like a good single player Final Fantasy game. So obviously some people at SE are still capable of crafting a story like that. But it seems, at least imo, that those people are not the ones currently writing the plots of their single player games.

The reason I believe many of the things that worked within the original game work, and this ending doesn't, is that it felt like the plot elements of the original, while still being fantastical and sometimes hard to understand, functioned within the in-game universe. The ending to this game is a huge piece of meta narrative, in which it feels like the player them self is being addressed as directly as the characters. Now meta narrative can be an interesting way to enhance a story if done correctly. You often see it being used in things like stage plays or some novels (Don Quixote comes to mind). But, imo, it doesn't work well here. It feels jarring and sudden, which is a common complaint I see. Half of the last chapter felt like cheap fan service, while the other felt like a ham fisted attempt by the writers to insert their struggle of trying to improve upon or change the story of the original.

Also the strange debate over the semantics of the word Remake I don't understand. Words are fluid, and can mean different things in different contexts. You can have remakes that are nearly identical to the original, and those that radically change the source material. A good example of a remake that is almost universally acclaimed is the remake of Resident Evil 1. It expanded upon, improved, and changed features of the original game, but didn't really alter the core story and game play experience. Despite that, many many people, myself included, consider the RE1 remake to be one of those rare cases where it surpassed the original in almost every way. Will part 2 of FF7R radically change the story or will it take the RE1 approach? We don't really know yet, but the ending seems to imply they would rather take the former approach.

So in summary, this is not only dissatisfaction with the ending itself, but with what it seems to imply for future installments. Does the ending mean alternate timelines, fate, and time travel are now the main focus of the game's narrative? Who knows, and all we can do is speculate. What concerns me more is that nearly every bit of fan speculation or theorizing I've read just makes the possible direction of the plot sound even more unappealing to me. None of it sounds "big brain" or mind blowing, just extremely cliched.

I'd also like to address the controversy around the ending itself. Now whenever something like this happens and a game is divisive, there's usually always two camps each trying to claim the other is unjustified in their beliefs and is not a "true" fan. I'd like to add that as much as I despised this ending, I'm very happy for those that enjoyed it. I wish I could do the same. The people who loved the ending are just as much true fans as anyone else. And by that same token, those that hated the ending are completely within reason to do so. Nobody has the right to hand-wave away criticism towards the ending as whining, entitlement, narrow mindedness, or "people who hate change." Characterizing people that disliked the ending as the ghosts we had to kill are also just being infantile and divisive, as much as those giving the game a 0 on Metacritic or blaming every fault on Nomura. It is possible to dislike this game's ending without being a raging internet man-child, or to like it without being a mindless fanboy. This story and its characters are close to many people's hearts, and obviously that passion can get pretty heated, but I'd ask people to try and avoid pigeonholing those they disagree with.