Oh, sure, that much I know. But the exciting part is that ghosts - as already detailed in the core book, and in bits and pieces in Mage and so on - are not at all playable as characters. Just echoes. Geist, therefore, must be something different, and based on Changeling and Hunter and the big three, it will also be quite different to Wraith.
But beyond that...? Who knows? Will the characters be actual ghosts? Will they be halfway between living and dead, like some of the Orpheus stuff? Will they be living people cursed to interact with the dead?
Could be any, all or none of those. And I'm excited precisely because I don't know!