This is my first time here. So being the law abiding n00b I am, I went to the “New Posters” thread, and read this “Squall of SeeD’s” post about how Aeris was never intended to live, or to be revived.
Well Squall is wrong, because she was intended to live. And Tifa, was to have never existed.

"Actually, we only had Aerith at the beginning, and Tifa did not exist. But on a Sunday evening, I phoned the director Mr. Kitase and suggested 'Let's kill Aerith and put in Tifa' (laughs). So now we have two heroines, and we never had an event where one of them dies." ~Character designer and the story writer of FFVII, Nomura Tetsuya

From-Final Fantasy VII Kaitai Shinsho

It’s virtually a technicality, but it’s there in writing. She WAS intended to live.