I'd be interested in hearing your view-point on what was "not artistic" or "poorly written" about the Godfather. One has to keep in mind that in works of Art/Entertainment (for example, music, painting, movies, books, and even food) THERE IS NOTHING THAT IS OBJECTIVELY ARTISTIC. There will be people who like any movie (wheather it's comedy, drama, suspence, sci-fi, gangster...etc) and will consider that movie is the best movie of all time. The same goes for books, music, paintings...etc.

As far as I know, there were never any rules that limited "artistic works" to certain guidlines. Remember that many artists (like Amadeus Mozart and Beathoven among thousands of other artists) were considered flops during their life-times. However, their artistic-nature came on eventually. That is a classic example of the different tastes of the people who make the definition of what's artistic.

As was pointed above, you are entitled to your own opinion of how artistic the book is. And so is Puzo (RIP) (referring to the book not being his best work). However, I'd disagree. Although I do agree that nothing he wrote after The Godfather was better (personal-artistically speaking) than The Fortunate Pilgrim, but I still think that with very little modification of some sub-plots, nothing that I have read could be better than the Godfather (not that I can think of anything that is better than it now).

ps: I don't mean any disrespect to anyone here, but this thread kind-of reminds me on the movie Amadeus (about Mozart). Where some rival-musicians' criticism was that the works had "too many notes". I used to laugh my eyes off when they said it. "...exactly which notes did you have in mind..."