I'll admit, I'm biased about this. My own religion requires couples to participate in a formal marriage preparation program before getting married. My wife and I found that program so beneficial that we volunteered to become presenters after we got married. (Note that although this preparation program was required by my religion, the program itself wasn't primarily focused on the religious aspects of marriage, but on the practical stuff: communication strategies, finances, decisions about children, etc.)
To me, it's a no-brainer that couples who confront these topics before getting married are going to fare better, but I've been surprised at how many of my peers were not interested in any type of marriage prep program when they were planning their own weddings. Perhaps they see marriage as something that's so unique to the couple that outside counsel isn't helpful?