Well from the gamers perspective I think it's clearly already affecting us. Nearly every Japanese publisher has from this gen made the majority of games westernised - and they clearly rely on the western markets more then ever before. Square Enix bought EIDOS for this reason, and seem to be trying to make Final Fantasy more and more America friendly.
Of course it's not all just cause of the economy, it's natural for any company the size of Capcom or SE to expand, and it was the Western market they were slacking in. However I think SE's accquisition of EIDOS was clearly for one reason only - the Japan market is at threat and SE, a company who previously took 90% of their revenue from Japan, has to find alternative sources.
It seems most of the 'big publishers' are positioned well enough to cope now though, very few still release games aimed specifically at the Japanese market.