Based on what I've been reading, it will be touch-screen and pearl e-ink. This will give me my most-wanted improvement: better battery life. That's really my only big gripe.
Whether they could do that for $99, I don't know. The newer pearl e-ink screen is just an upgrade - I mean, the Kindle didn't get more expensive when they added that. In fact, it got cheaper - mostly from market forces, but still, it cannot be that much more expensive than what the current Classic Nook is using. So it looks like longer battery life may be a done deal. I hope.
Touch screen does seem like it would be more expensive than $99, but it would give Nook a big selling point over Kindle, so which do they want more - better features or lower price? We shall see...