If you want to get the upgrades for intercontinental flights, it's well worth the money to subcribe to expertflyer (I think $99 a year last time I renewed). With this I have no trouble on using the PMUs for upgrades to Asia with advance planning. You will still have to buy a M-class fare (around $2k for the cheapest cities in Asia), but at least you have 3 RTs per year (6 one-way certs).
The old NW Platinum certs were frankly much better (upgrade from any paid ticket basically), but it was only 2 one-ways or 1 RT per year.