I think lowering the population is one of the best thinks that could happen to Japan. The politicians will have to figure out what to do about the lower tax base, but that's what they are getting paid to do.
Seems like the govt. is approaching this problem more seriously than a few years ago. There was a plan put out by someone in the govt. to increase the birthrate which included:
60,000 yen one time payment for every new baby.
Limiting the number of women entering universities. Their thinking was that if they couldn't make to college they would get married and start pumping out kids...