Ideally, in Eco mode all EV's should free-wheel coast when you lift your right foot off the accelerator pedal. It should be easy, and this would encourage coasting, and you learn to minimize how much acceleration you do. Put ALL of the regeneration on the *brake* pedal; you know the one for stopping.
An added benefit would be the ability to rest / stretch your right leg on longer drives. Lift you foot to coast, and relax all the muscles -- much better than having to concentrate on some dial to find the perfect position...
The Honda Fit EV apparently does this in the Eco mode -- the Leaf and the i MiEV (and the Focus? and the Mini E) designers should all learn from those of us who have been practicing ecodriving aka hypermiling!