I'm confused by unit colours and was hoping someone could help me out by explaining the system. At first I thought orange meant Protestant German, but I'm not so sure now. Bohemians and Hungarians are both red, Dutch, Germans and I think the English too are orange. Catholic armies can also be orange (Spain), grey-blue (Austrian?) or pale blue (Catholic German or Bavarian?). I can see why every German state can't have its own colour!
There seems also to be a blurring of religion and nationality which I think needs sorting out. Some units' nationality is given as "Protestant" (not a nationality surely), whereas Protestant Bohemians are identified by their proper nationality. The situation was very complicated with Catholic allies of Protestants, the Ottomans and Catholics leading Protestant armies! Maybe simplify with one colour for Protestants and their allies and another for Catholics and their allies, with nationality given in the tooltip? The manual doesn't say much about this.