Avion isn't 100% correct. The midfield is beeing bulit between the runways.
But between the terminal A and B the new 'airside centre'. This part should be the future angle point for connections and so on. From there the new underground people mover will bring the pax the the new concourse midfield.
Doesn't all this construction seem alittle bit unnecessary at the moment anyway, seeing that their is no Swissair! And with the consolidation in European airlines coming, many airports will lose out in the hub statis. I see Zurich losing out to other hubs, like Paris.
With the actual situation the new airport will be far to big! That's correct. But they planned and begun building the new concourse and all the stuff before the Swissair disaster. And to stop now after half time doesn't make sense.
So maybe will have a 'ghost airport' here in ZRH, like in KUL for example. But I hope not too deserted...