Since the merger of Delta and NWA the FF program has been changed to the chagrin of all.Delta has increased the mileage requirements making getting award tickets impossible.eg I spent 150K miles for a business class tkt last year for LAX-SYD but this year the mileage requirement is 240K on "low dates:" and 305K miles (yes 305K miles) for "med dates".Incidentally in most months Delta offers only 1 "low" date and only 2 award tickets on those flights.
Also the SW upgrades are useless because the M fare which is the minimal requirement is 4-6 times the T fare.So Delta has pulled a fast one on us that have flwon and enjoyed NWA all these years.