The whispers didn't want Cloud to fight Sephiroth so early, so with Sephiroth moving to fight them at the end of the remake, that caused the ultimate Whisper Harbinger to come out and subsequently be defeated, which gave Sephiroth more power.
I'm very reluctant to accept any of that as insteresting and even part of the canon since that none of that was even hinted at possible before, the most esoteric thing 7 had that I can think of is the idea that some people can navigate the lifestream after death, but now we have timelines and fate ghosts and time travel, my problem are not the changes, but that the changes seem too extreme and incoherent with the universe we already know, it's fine if we have time travel in 8 since it's a brand new universe with specific rules, but introducing that element now to 7 starts diluting this universe with new gimmicks, remember when Hojo uploaded his brain to the internet? it's canon now, it's mysterious and surprising, that doesn't mean I have to like it.
Besides I really don't trust SE introducing new elements to stablished stroies, especially time travel:
XIII-2: New time travel story out of nowhere (I don't care much for that universe but it's such a drastic departure it's almost unrecognizable as the same game, LR even more so)
3rd Birthday: Main plot is time travel now for some reason, we all know how that turned out.
KH3: More time travel and timeline shenanigans, this game was already crazy so who cares, but Nomura got bad habits from it.
XV: Even in the same game we are introduced to a very late time travel plot device to fix a gameplay problem, the writers really coulnd't think of a best solution, so hey, time travel, why not.
Time travel and timelines have always been a cheap writing gimmick, unles the story is designed from the begining to work with those elements, it's a lazy excuse to keep padding and "fixing"stories.
As long as it's not a case of infinite realities, then the world still has meaning, limitation, and consequence.
I would argue one more timeline already removed all menaing and consequence for the original timeline, which is the one we care about, they basically abandoned the orginal game, the one we like, to hop into a brand new one, kind of insulting if you ask me.