I'm wondering why they didn't choose Hannover as it is somewhat in the middle of Germany, has an international airport, is accustomed to heavy spikes in tourism and has the world largest fairground due to the Expo in 2000. Hannover also is a major crossing point of railway lines and highways (Autobahn).
Hannover itself may be centrally located and quite reachable, the Messegelaende in Hannover is not. There is, for example, no tram service going from Messegelaende to the city center between 2130—0400. With the last talks of the day usually lasting until after midnight, that's clearly unacceptable.
I am not really aware of a suitable location over here - sadly. Yes, the exhibition area is huge, but does not really fit their needs. Would have been neat, anyway.
