You're right. But even when you don't have the ghost the team work is better. I think its a mixture of the play style and the map styles. You don't run around as much as other games cause that gets you dead. It has a little more of a creep and peep feel if you know what I mean.
Anyway, yes this game is free. It's being released by Steam's Green-light Project. If you know nothing about this you should look into it. I found my new favorite game Heroes & Generals thru Steam's Green-Light.
Anyway, I hope this generates enough energy for them to make a new game play mode. The Ghost was such an original idea i would like to see the stage two concept.