The more the nuanced the take, the less people will be drawn to it. Hence the popularity of the Bible and the Koran etc.
I'm not familiar enough with the Qur'an to comment on it.
This is a feature for its followers, because they can and do pick and choose the parts they like and ignore the rest.
Its really the songs / performances that carry the Christian belief; few people actually read the bible but they can all re-iterate to you that Christ was born in a manager because there was no room in the inn (not in the Bible).