Duke = Germany?
Duke being Germany really rubs me the wrong way. Maybe (probably) it's because I'm Dutch.
I don't think that Duke can be either Germany or Japan - no one really hates those countries as much any more. In Europe, only the lowlands and the French still have a "not so friendly" relationship with Germany.
I'm sticking to my initial recommendation of Duke = France: arrogant, despised by many, but once you're there, you become a huge fan of the culture and people (minus the Parisians). It just makes sense. Plus, look at our French WW1 mascot.
Other possibilities for Duke: South Korea (only recently prospered, faster growing economy than nearly all of Asia, developed), Brazil (countrymen are crazy about one sport only and they're damn good at it, beautiful place, only became relevant in the last 30 years or so), Switzerland (smart, clean, beautiful, good with money, balanced. However, no one hates Switzerland)
Criticism may not be agreeable, but it is necessary. It fulfils the same function as pain in the human body. It calls attention to an unhealthy state of things. - Winston Churchill
President of the "Nolan Smith Should Have His Jersey in The Rafters" Club