So, while I don't agree with the OP on the Coach vs Business/First argument, I have the same feelings about Business/First. I don't mind flying coach on a 4hr flight to Vegas, but on a long-haul international, I'm inclined to want to splurge for the Business ticket.

However, I'm not sure that I "buy" the argument that one needs to travel First. To me, the difference between coach/business is much greater than between business/first. Sure, there are extra ameneties that are included in First, but not enough (IMO) to spend the extra 50% or 100% miles premium that is required.