my complaint about the Bible is that because so many people know the story, it's not really a wise idea to deviate from it. a few errors with Abraham and Isaac (isaac was 20 when abraham was asked to sacrifice him, not ten; they took two servants with them and left in the middle of the night so sarah wouldn't know; it was a three day journey to get to mount moriah, not simply over the next couple of hills).
wish they would've shown the story of joseph. one of my favorites in the old testament.
as for the vikings, it has potential. the conflict between the king and the main character (who's wife is surprisingly horny) could be a lot of fun to watch.