I live in MSP most of the year, so I'd love to have some Nonstops from here to SIN, BKK, HKG.... but....
I also wonder which cities NW should fly these Nonstops from.... I think NW's other problem is that their hub cities in the US (MSP, DTW, MEM) are rarely Int'l tourist destinations, unlike East and West coast cities.
Also, while it'd be convenient for Midwest and East-Coast-based NW pax if you only do Nonstops from, say, MSP-HKG-MSP, and DTW-PEK-DTW, you'd be cutting off all the pax who connect at NRT from LAX, SFO, PDX, and SEA, unless they wanted to fly an extra 6-8 hours, and connect in the Midwest. If NWA did their nonstops out of the West Coast (say, LAX or SFO), they'd be needing to fill several planes with connecting pax from the Midwest.

If you wanted to keep the NRT connections (for west coast pax) and also have the new Nonstops, the US government would have to renegotiate Air Treaties with all of these countries separately.