I wonder how the OP knows so early in the year that he/she will have exactly 14 nights (including any credit card night credits). [In many countries, I'd even add that the OP might not be in the same job by the end of the year, but there's much less worker mobility in Japan.]

It's hard to see how the Platinum benefits (even compared to nonstatus rather than Gold) for 14 nights would be worth $2000 plus whatever travel costs. However, it OP is sure that travel will be dramatically increased again the following year, this might be worthwhile but I would try to find some weekend breaks or vacation stays rather than just mattress runs for some of the nights.

Another consideration might be whether OP is close to achieving lifetime status.

ADDED. Qualifying on stays rather than nights results in no SNAs, which can be valuable if used strategically in Asia.