Talk:Princess Celestia/@comment-4604642-20140318111529/@comment-5837525-20140323160947

Were those episodes rewritten with different characters as stand-ins for the characters that were used, it would've either been not as emotionally impacting or it wouldn't have even made sense.

Who would Scootaloo have been able to talk in Sleepless in Ponyville? Rainbow Dash? Not possible; she was the very source of Scootaloo's inner conflict. Rarity or Applejack? Also not possible, as each of them had their own sibling to look after, and Scootaloo wouldn't have been to connect with either of them on a personal level.

Could Celestia have been sick in Three's A Crowd? Yes, but then the episode would have to be COMPLETELY rewritten. Twilight's friends would have been more open to the idea of taking care of her while she spends time with Cadance. Conflict resolved within ten minutes.

You can't replace one character with another without rewriting the scene they're in to fit their presence.