I'm really looking forward to seeing all the girls get more fleshed out in terms of characterization! I don't think all 30 characters with CDs will appear, but a few is more than nothing. Although, some characters will probably get shafted if it's like the original idolmaster anime, and some of my favorites probably won't appear at all.
I hope the New Generation girls don't hog the spotlight though. They just... Lack the appeal and charm of Haruka, Chihaya, and Miki?