If the Norse god were portrayed by purple or green people, it wouldn't bother me a bit. I wouldn't take this as a history lesson either. If I cared enough, I'd read some reliable sources on Norse mythology and history.
I meant "artistic license" would allow the creators to veer off historical facts and established culture. It really doesn't bother me. Granted many people learn history from the movies, but is shouldn't be the responsibility of the artist to educate them. Like any other expression, producing art isn't necessarily tasteful or ..non-arrogant. If the BBC billed this series as a historical piece, then BBC should be criticized.
Please don't spray-paint the original Starry Night. But if you're so inclined to spray paint a ..copy, I may even buy it from you!