Japan Rail pass or not?

I already made up my mind, or at least that is what I thought!

But now I start to question it... Should we travel outside Tokyo this time or not?

I always use this pass when I go to Japan because it is very convenient to get around ALL OVER Japan. However this time I said.. let's just stay in Tokyo and it's surrounding. But the other day I read the article about the new Hakodate/Hokkaido Shinkasen line. It would make it possible to reach Hokkaido within 4 hours from Tokyo. So a one night and two days in Hokkaido.

We'll see how it will end up...