Luna's dialogue was written by Lauren Faust in the pilots, and Mitch Larson in "Luna Eclipsed" Discord's dialogue was written by Mitch Larson. And it's Tabitha that does Luna's voice, not Nicole.
Saw an interesting analogy on PonyChan a while ago comparing the writers to the Beatles: Mitch Larson and Meghan McCarthy are John Lennon and Paul McCartney; it's so hard to tell which one is better. Amy Keating Rogers is George Harrison; very good when solo, but often overshadowed by her more popular co-workers. Charlotte Fullerton, Cindy Morrow, and Dave Polsky are Ringo Starr; are often not cared for, but there are some fans out there. Lauren Faust was Brian Epstein; made sure everything was in check, until she left. Mary Williams is Yoko Ono; a hack who could very likely disband the whole group. Chris Savino was Pete Best; stuck around for a year, and then left. Soon enough, there was a reply which compared them even more: Mitch Larson would be gunned down by a mad brony. Meghan McCarthy would try to keep the writers together, but would move on to write for other shows. Amy Keating Rogers would have a promising career after ponies, only to be cut short by lung cancer.
