...I'd say Berlin. And here is why.
Berlin is the largest city in Europe, with the Brandenburg /Berlin area home to about
6 million people. It has no service, and has been poorly served by Lufthansa for years
and since reunification Lufthansa has shown little interest in expanding, forcing people
through its other hubs instead. The City of Berlin and the state of Brandenburg have long
argued for direct long haul intercontinental service from their city but heading towards the East...this has
been largely blocked by Lufthansa's lobbying efforts. EK
is restricted to flying to 5 cities in germany,
which it already does and therefore cannot add anymore and Etihad I believe Berlin is specificially excluded
from flying to for UAE carriers, hence the back door via their Air Berlin investment.
Now consider Qantas should be have to fly there using Australian bilaterials... and 5th freedom rights between
germany and DXB
(or pretty much anywhere between australia and Germany) it could have this flight fed from the entire
network, from as far away as south africa to tokyo. I dont think they'd wanna push it too far just yet, they have
to get the basics up and running soon. But where ever else EK
meets staunch resistance but Australia carriers have
ancient rights to fly there, largely unused... I can see the potential.