You know the FF7 PC version also has the Aeris's flashy appearance at the Chruch. The position of the Ghost Aeris is different in both PC and PSX, meaning the developers has changed that bit without removing the Ghost Aeris intentionally.
Sqaure released FF7 for PC way after they have released FF7 for PlayStation.
So if the Aeris appearance at the Chruch was a glitch as you all think, then why didn't Square fix it before releasing the game for PC?
Anyway, regarding the theory, I think I have found something related in AC. During fighting against Sephiroth, you will see this first scene:
^ The church.
And a few later second, you will see this second scene:
Aeris was praying.
Those scenes seem similar to the FF7 event (Aeris being in the Chruch after death).
Those scenes are connected! It makes sense!
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Aerith's Knight, how about this one?
What does it look like to you?
