I like @medford's idea of an international-themed restaurant. That way, you could keep Panda Express (which some people do like...my wife is one of them) and even, I guess, the pizza (although I've found that the pizza at Festhaus tends to be the worst in the entire park; not sure why). Add a taco bar, some German food...change the burrito shack to a place that serves grilled brats and sauerkraut.
Festhaus used to feel special. That was where they had the most elaborate shows (the ice show was in there for a bit) and it was a really cool deal to head in, get a meal and take a break for a bit. Now it feels like an afterthought; the food is usually subpar, the shows have to compete with the arcade (do they even dim the lights for the shows anymore?).
I'd love to see them really focus on Festhaus. Put a standout show in there, get rid of the arcade games and TV screens (make it a live entertainment destination). Get good, unique food in there. And move in a good bar with a dozen taps and other options. It's so tossed off right now, but it could be as big a destination as anyplace in the park, especially for families with young kids or older visitors who aren't riders.