I've been through this 'ADIZ' a couple of times now and haven't noticed anything strange at all. There was a bit more Chinese chatter on Guard on the first two days but nobody could understand what they were saying since they chose not to broadcast in English.
I'm all for the Japanese stance. We're flying on established airways with the Japanese FIR, so there is no need whatsoever to copy the flight plan to China. If the Chinese were to hurl a missile at an airliner while they are flying from e.g. Taipei to Tokyo there would be all hell to pay from the international community and the Chinese are not so stupid to ignore that.
In order to save 'face', the Chinese just have to remove their demand regarding themselves as flight plan addressees within the Fukuoka FIR. They can keep their lines on a map, business can continue as usual and everybody can go back to mistrusting each other in the region.