the JR pass is almost never a good deal. you need to do a significant amount of travel over a significant distance in a short amount of time and is a very inconvenient way to travel compared to just using an IC card plus adhoc shinkansen tickets.
I priced out a complicated multi-city itinerary for a family visit and even with a lot of long distance trains it basically broke even.
There's lots of things that the JR Pass works for that aren't Shinkansen and they used to add up even if it was just $10/day, and you didn't have to worry about it. Just the Narita Express was $30-40 one way.
With the new pricing... not so much. Just get SUICA unless you're going all the way from Sapporo to Fukuoka and back.