IT's mostly that her 'regular' personality is such a stark contrast to her nightmare moon persona that lends credence to the multiple personalities, I think. After all, Nightmare moon was completely confident. Luna was downright petrified of her sister. Yeah, because she though she was going back to the moon, but Nightmare moon would have lashed out, not cowered. If they were the same personality, there would have been lingering resentment even after Celestia forgave her - 1000 years is a long time for anyone - but Luna was pretty clearly taking the 'all my fault' approach.
I wouldn't call it a split personality, but it's probable someone was manipulating her for their gain. That, or Luna is a very,
very good actress. or, in a third and by far the most disturbing possibility, nightmare moon was in fact Luna, through and through, and the elements of harmony...
cooled her down a little
@Kuroi: Both times I've submitted I think he sent me a 'off to the prereaders' within a day. I think it varies depending on how many fics they get, but it's usually another day after that until he gives you the yes or no? How long have you been waiting on it now?
edited 4th Jun '11 9:29:47 PM by kegisak