By of disclaimer: I haven't brewed a Dunkel yet, so I haven't worked out a recipe or discovered one that I have confidence in, but I've been researching a lot and I'm going by the mistakes I've made on other German style beers. The right way to do those great German beers is by skillfully mashing very simple grain bills.
As homebrewers (and sometimes very amateur ones, at that, speaking strictly for myself) we have access to a lot of shortcuts and specialty grains that can mimic the qualities we want to impart. If we use them judiciously, we can get very good beer along the way, but we're ultimately on a journey of turning simple starches into very complex beers.
The thing that I'm realizing lately is that beer recipes can be very deceptive. We think that the ingredient list is the most important thing. It is an important part of the process, of course, but how we handle those ingredients is what makes the beer. The most perfect grain bill, whether simple or complex, will result in a pretty crappy beer if it's handled badly.
OTOH, 10 lbs of Pilsner in the hands of a real brewer will, given enough time, be transformed into something transcendent.