Lie flat is everything for me in J. Sleep is key. Service is a nice bonus and I will seek out better carriers if all else is equal. I also doubt NH will be cheaper than AC so I really don't see the point. NRT doesn't make a big difference to me. I'm always picked up so I can work and reconnect after the long flight on the (long) drive into/through the city.
JAL put 787s on YVR due to engine issues. They can't fly through certain types of clouds so to avoid issues they shuffled them around to routes where such formations are less likely to exist.