OTOH, TAR has been good at revisiting some countries, while managing to create distinct legs that focus on different aspects of the nation's culture. The best example is definitely France, which has hosted 7 legs to date. However, Paris has only been visited twice, while the other legs took place in other areas and were unique in their own ways. Other good examples are Italy, Australia, and Brazil.
I would agree with Caelestor that a good country to use as an example of better variety by World Race Productions in Amazing Races is France. My statistics, however, indicate that France has only been visited in 5 Amazing Race seasons and a total of 9 major places (not 7 as Caelestor indicated). "I'm from Missouri." Where are the visits beyond these:
AR1 - Paris, Marseilles
AR4 - Paris, Marseilles
AR6 - Ajaccio (Corsica)
AR10 - Paris (plus Caen if you are counting small cities)
AR16 - Verdun, Reims/Epernay
However, here are 3 better choices for diversity of the major places visited (meaning not Paris 3 out of 5 visits to France):
India - AR1 (Delhi, Agra, Jaipur), AR4 (Cochin, Mumbai, Alleppey), AR5 (Lucknow, Jodhpur), AR 10 (Chennai), AR12 (Mumbai), AR13 (Delhi), AR14 (Jaipur)
Germany - AR3 (Munich, Fussen), AR6 (Berlin), AR9 (Stuttgart, Bavaria/Munich), AR14 Bavaria, AR16 (Hamburg)
Italy - AR1 (Rome, Modena), AR4 (Venice, Cortina d'Ampezzo, Milan), AR9 (Palermo, Segesta, Catania, Syracuse), AR12 (Ancona, Empoli, Florence)
Note - not counting transportation mode transfers in Frankfurt or Munich or Milan or flight connections in Delhi or Chennai or Mumbai.