One of my first thoughts once they clarified she was a replacement was that maybe there's some reason (union stuff or whatever) she couldn't admit to being in the old games, but can now freely talk about the new ones, so they had to act as if she was new. But her cover would be blown the moment the game comes out and she sounds exactly the same... I haven't been able to listen to the clips people have posted yet because I'm at work, so I have no idea if she sounds close enough for that to even be plausible.
Also, unrelated, just got an Atlus Faithful email, they're going to be streaming some Ultimax at 2PM pacific time today
http://www.twitch.tv/atlususa