Hurray! A followup to NieR has been announced. Here's what we know:
Director: Yoko Taro
Composer Keiichi Okabe
Square Enix is publishing and the studio will be some sort of combination of Platinum Games and Access Games (?)
The song used initially has a melody reminiscent of Ashes of Dreams, especially when it gets to 1:14 in the trailer. I suppose that doesn't mean too much. Then, at 1:24, right when the girl is revealed, it has a melody very reminiscent of Yonah's theme (Check here at 0:14). So, I think it's probably just Yonah as you would expect. I had initially wondered if it might be a young Grandma or just a new character. So, NieR ending spoilers:
If they go with a cannon ending D, NieR Gestalt has been erased from the universe to save Kaine and Yonah grows up with Kaine. That would make sense given the sword she's using. Kaine would have taught her how to fight.