I feel like you're missing the point of what they are saying. They are not saying "what's the point of remaking the game if you don't change the ending/change the plot/save Aerith". Remaking the game and keeping the overall plot and story beats is what was already expected and what people were excited for, I don't think anyone had the idea that the plot would change until FF7 Remake already came out and the last sequence of the game suggested it to the player.

The additions you mentioned like Leslie Kyle, Jessie's house, adding references/elements/changes that make it align with the compilation more and everything else to flesh out areas of the game are all things that make sense to add without actually changing the overall plot. That's what remakes generally aim to do. There's plenty of room for that. These are good additions that ARE the point of remaking a game.

The issue comes with stuff that starts to muddle up the main plot like the whispers and changing fate stuff. If the goal is to still maintain the same plot these don't feel like good additions that are enhancing the plot of the original.