I prefer NH business even in the old plane compared to UA F. IAD-NRT sometimes operates the old config but that might change. I don't mind because it departs too early to sleep much. The NH cabin is huge and airy whereas the UA business and first cabins are very claustrophobic with 8 people across in business. The F cabin is much smaller and the seats are wedged in there with narrow aisles on the 777.

With business staggered in NH business you effectively have 4 people across in the cabin whereas UA packs in 8 people!

Note that UA is increasing its miles required starting Feb 1. If you change anything after that then you pay more points. Note that including TYO-OSA will increase mileage requirement in future even if you fly UA IAD-NRT because there is an upcharge if you include *A flights on an award ticket starting Feb 1.