LH do quite a lot of seasonal routes around Europe. Germans are voracious travellers, with the Euro -> Pound conversion rate as it is, having a holiday probably looks quite attractive.
I've been astounded by the number of Germans I've met who travel regularly to Dorset and Cornwall, primarily for hiking/walking holidays. I guess you just don't appreciate it as much when you're that much closer to it....
BRS-FRA is a workhorse feeder route, which needs to become a primary deliverer of traffic into the wider LH/*A network. DUS-NQY is a summer once-a-week only holiday route.
I'm on tomorrow's FRA at 06:40 (hello to any fellow travellers - I'll be in the lounge), and I suspect loads will be load. It's just going to take a dig in to get people off the KL AMS route, and to bring people away from LHR->Asia/Africa/Far East etc.