Back then, playing it as a kid, that moment was a huge shock and motivator to beat Sephiroth. Any respect or awe I had left for him went out the window. I'd like to think any new players would have a similar effect, especially considering you get even more time to grow attached to her (that Gold Saucer date is gonna be something in the Remake...)
Anyway, I think adding it as a non-canon 'thing' in a NG+ run would be good for novelty or even replay value, but I'd personally be disappointed if they allowed you to change her fate outright.