I think you really want status for your long-hauls (for priority during standby or service disruptions); there really aren't enough flights to worry about maximizing other benefits. Best choice would be status with whomever you will be flying to NRT; VS is probably a good choice, their LHR clubhouse is spectacular. In general VS has a great seat and ground product, which makes up for any shortfalls in their in-air soft product. Plus the VS flight attendants are quite notorious in NRT, fwiw.

The advice to consider BD and LH is sound; I prefer OW, but LH has improved tremendously in the past 3 years -- and has just announced that it is re-investing record profits into improving their F/J products. While BA is not.