I had a couple other suggestions, too, if you're interested:
For one, it might be better to separate the "Fragen zum Festival / Questions about the festival" subforum into English and German, and move them to the deutsch/international boards instead of the "Everything about WOA". Not really sure why it needs to be in the section that gets archived after every festival, since a lot of questions apply just the same year after year. And I think a lot of English speakers avoid that area for asking questions, and so they come here. Like, we've got two stickies entirely about Wacken questions.
I think it'd encourage far more questions (and registrations) by separating them by language like that.
Another idea you could consider is adding a subforum in both the German and international sides for practicing the other's language. I've noticed a bunch of people want to learn English/German, but are too nervous to try and talk to the people on the other side, usually because they don't know anyone on the other side, or because they feel like their attempts to practice aren't welcome, or both (on top of the usual fears of making mistakes etc). A separate area entirely designed for that purpose would make people more likely to try it out. Plus, if it works, people from the two sides start to get to know each other, and they'll start posting on the other subforums/"Talk". And then you'll have more activity on both sides.
@Everyone else, what do you think about that? Good idea, bad idea?