Analysis Is Magic
You mean, aside from Tress MacNeille?I would pick Regina King. She primarily does live-action, but I love her work as Huey and Riley Freeman, and MLP could provide some great use for her.I want to resist the temptation to suggest more geek-stunt-casting, but since they've fought Q, they might as well fight GLaDOS. Get Ellen MacLain to voice a prototype AI who has been programmed to read all of Twilight's friendship reports, but is learning all the wrong lessons from some of the... less effective episodes. It'd be a great opportunity to revisit/clarify some of the more unintentionally-problematic subtexts thus far (FPK, MMDW...)
Ellen MacLain would be AWESOME!But I don't really like the idea of an AI, that's way too advanced technology for ponies. (I'm one of those people who doesn't like the electric lights in Read It and Weep, I'm afraid.)Maybe Twilight tries to create some kind of Friendship Golem from her reports to Princess Celestia, and it learns all the wrong lessons. Sort of like that Adventure Time episode with Goliad, but less... Adventure Time-y. (I love Adventure Time, but MLP should do its own thing.)Hmm... only problem is then we have to revisit One Bad Apple, and I like to pretend that episode doesn't exist, except when I'm complaining about the fact that it exists.
All of the YES.
I adore Grey DeLisle, but I don't want her to voice a pony because her voice gives me pantsfeelings, and that would be creepy.