My first post, 4 years ago, was complaining about lack of saver business class award to Asia on NW.
WBC Standard Award is almost impossible between NRT and DTW or MSP, even if you plan one year ahead.
The best shot, is to go JFK/LAX/SEA to NRT. SFO is also possible sometimes. Depending on your city, either you drive to the gateways I mentioned above, or ask if the following route is allowed
Your city-JFK/LAX/SEA-NRT-Asian Destination City
for award travel. I face the same problem (see my other post) and try to find a solution.
I am glad to report that NW has greatly increased WBC awards ever since (they changed name from Standard to Saver). ^^