I've always understood the argument to be that a wide body offers a more spacious environment (even if you personally don't have much more room in economy) when you are cooped up in a plane on a long haul trip. Despite that, many people seem to love the top deck of a 747 for its smaller overall size and more intimate atmosphere. There might be a contradiction in there somewhere.
I'll settle for a business class seat as long as someone else is paying.