Sorry, but isn't one of the major problems of AB TXL?

BER would have allowed/will allow AB to properly hub in one place (for example pulling some long haul flights away from DUS) and for other oneworld carriers to add traffic there (e.g. AA could switch its flights from FRA to BER, which it can't now to TXL due to the latter's capacity issues).

And of course BER is now slated to open...27 October 2013!!!