Europe benefitted greatly from the (more generous 100Euros) price cut. In Japan I doubt a ~50$ price cut will make any significant impact (35~45k IMO). As for Super Mario Galaxy, even Everybody's Golf and Dragon Quest Swords moved systems, their beloved plumber won't? And if that happens, then I agree with FishyJoe, why should MGS4? Or even FFXIII?
My themeforest portfolio:







