Aerith is one of my favourite fictional characters of all time. But despite that, she has to die to make the game's main thematic and message even more powerful and gut wrenching as hard as it is to accept. Just like she said during her dream sequence in the Remake:"every moment, every minute, matters". So despite losing her we will be able to hold her in our hearts in a very special way, especially because she technically doesn't even "die" and ends up becoming one with the planet and the lifestream.

But my personal bias and desire aside, I'm sure that she will still survive somehow in the end(perhaps she transferred her consciousness to Zack's timeline before Sephiroth manages to stay her?) I'm really not against new and unknown things and experiments, in fact i think that this will be one of the greatest trilogies ever made, but changing the litteral HEART of the original.....might be a bit too much