the one thing is really intriguing it is sudden drops and rises of popularity in opinion polls. how on earth Hatoyama got initial 70% then if for no apparent reasons his rating tanked?

I think there should be questions about selection process used by japanese pollsters and if everything seems OK then there should be sociological studies explaining such political volatility. Do you know of any?

As for consequences of his resignation I think they should be minimal, I remember he only rhetorically tried to chart new course for Japan. Well oiled government machine is functioning albeit slowly.