I’ve had these feelings about FF7 for a loooong time, so I apologize for the length of this in advance.
I think they need to keep things true to the characters and setting they originally created. They need to forget that things like Advent Children existed, in fact they need to abandon most of the extended FF7 Universe stuff because it tears into the mystery and awe of the original game.
The sense of scale in Midgar was awesome, it felt like an actual city on top of another much less decadent city. Filling in the blanks for the ShinRa plot points felt kind of dumb, like we had to be shown just how evil everyone there was. In the original, they were evil because they didn’t care about life or the planet, not because they were actively seeking to kill and destroy. They killed and destroyed to protect their image and bottom lines! And Sephiroth… somehow he keeps morphing into this character who is trying to stop Cloud from existing. In the original he didn’t really care about Cloud. He was using Cloud as his most successful clone but it wasn’t like he was invested in killing him. Cloud was the one showing up and trying to stop him, he was always trying to throw a wrench in Sephiroth’s plans.
I think the OG guys want to make something new and divergent from the original and try not to properly remake the original because they know they will likely fail. Instead they give us an alternate timeline/worldline thing which ends up obscuring the subtlety and finesse the original story actual had. The original was more down to earth and steeped in humanity than anything the extended stuff has given us.

I don’t think it needs to replace the OG at all, I think it should bring the OG into modern day and rather than pad the story with explanation, just expand on what was already in the original. The expanded dynamics between Jessie and Cloud, or Tifa and Cloud, or Aerith and Cloud… (is this a harem anime?) actually felt a bit more inline with what I was hoping from the remake. The extra stuff that adds elements that were never in the original felt a bit like retcons, even though the remake might as well be a sequel if the prevailing theories prove to be correct.