The winners write the history books.

Everypony knows that beings like Discord, Nightmare Moon and Queen Chrysalis are completely, utterly evil. The victor has made it so, and therefore nothing can be said or done to change it. For now.

Pressure from recently defeated foes will bring Equestria to its knees, but none of them will be able to match the suffering brought about by the inevitable escape of an earth pony from her chaotic prison.

Right?

Or maybe, Equestria will change for the better.

No matter what the outcome, everypony will soon realise that nothing can be viewed in just black and white...

There will always be shades of grey.