The PAX Demo had 4 characters (the Assassins, not the generals) and no maps--By no maps I mean that they had a special, simple (kind of vanilla) map. They said that they gernerals would also be playable in the beta, but did not say explicitly that they would be playable on Thursday. However I had assumed that.
They really impressed me with the Rook. That guy has incredible animations. He has 3 towers above his torso and one has a wizard in it who will cast spells that can be amplified through a kind of wizard's tower, and another has archers that will shoot enemies, This is all going on as you're doing your regular attacks.