One, it's kind of racists with all of the Heroes being WHITE.
Actually... Thunder (I think that was his name), Whisper and Garth were from Samarkand, very African looking. Also, it's just reflecting the times. When travel was hard, ethnic groups didn't spread very much. In Albion, the natives have fair skin. That still goes to today in some areas of the world, in the Middle East you're likely to the majority of people who look Arabic. Same goes for Auroa. In Latin America, you'll likely find a majority Hispanic. In East Asia, you're likely to find East Asians. So on and so on. Albion isn't so far in the future that travel is easy and it can be as diverse as America or current day U.K.