JR East has brought back an English online reservation system.
The older "World Eki" system which closed a few years ago, allowed you to book Shinkansen and NEX tickets for all the JR Networks, however this new system is only valid for JR EAST/East Japan Railway Company, Shinkansen and certain Limited Express trains, and (like the old ekinet system) can only be received inside the JR East service area.
http://jreast-shinkansen-reservation...menu/menu.aspx
Key note:
-Reservations can be made from one month before your travel date up until 5:00 p.m. (17:00, Japan Standard Time) 3 days prior to your travel date.
Not a perfect system, but it gives some more options for those traveling.