One thing to remember is that American Gods was Gaiman's first novel. he had co-written Good Omens with Terry Pratchett, who helped Gaiman put his ideas into novel form as opposed to comic book script form.
The TV adaptation might be confusing to audiences who have not read the book, or do not have any exposure to mythological history and comparative religion, They also really make shadow's dead wife get more and more rotten! so grossssss. I think it may be the first TV show that deals with and shows sexuality in a organic and human manner, as opposed to using sexual attraction as a simple plot device.