I would say a 7 hour flight is definitely worth the additional miles to fly in Business Class if you have the miles to spare. It is true they don't release I or even R inventory on this route very often. IME upgrade from Y-C came within 12 hours of the flight for one leg and 2-3 days in advance for the other leg. So saver award availability would be tough to find. But of course the business class seats are going to be more comfortable.