My initial interpretation of the press release was that, as the MD-11's are retired, 777's will be shifted to the routes that are too long for a 763 to handle (ATL-NRT is the only current one that comes to mind), and 763's will operate almost all of the remaining routes, with narrowbody equipment being deployed on some current domestic 763 routes in order to make the 763's available for the international flying.
However, insurance issues aside (which I don't understand, since plenty of other airlines operate 777's to Asia, and even over the Pole), it is equally plausible that DL will abandon NRT entirely. With LAX, PDX, and the brief attempt at JFK service gone, not to mention NGO, KIX, FUK, and SEL, DL doesn't have a meaningful presence in Asia anymore. One token flight a day might be a waste of resources that could be used more productively on relatively lucrative service to SkyTeam hubs in Europe (CDG, MXP, etc.).
Then again, if DL were to codeshare with NW, an ATL-NRT route to feed NW's Asian hub would make sense...it will be interesting to see what develops...