Guess it depends on whether you're looking to get a job. In Niseko, Hakuba and a handful of other places, its far easier for foreigners to get jobs. Get a working holiday visa and you'll probably be able to pick something up, even if you have no Japanese. Especially in Niseko (you rarely hear any Japanese spoken in Niseko!)
If you're able to get by without working and want to spend a winter riding the best pow, then you should just hire a van and travel to different spots both in Hokkaido and down in Honshu.