Coasting and minimizing the use of braking (whether from regen or brake pads) is the most efficient under any scenario. Braking = energy wasted. Less energy is wasted when the braking makes electricty instead of heat and brake dust, but it still loses some energy.
Being able to switch between coasting and drive ought to be quick and easy. Too bad the only ways to do it are move around, but never quite being able to hold the sweet spot (with lots of fatiguing micro decisions) or to play with the toggle of the gear lever in and out out of neutral.
Perhaps auto pilot will eventually have a hypermiler mode which will make full use of coasting as much as possible.
+1 here, and to the OP as well.
Even if most people are satisfied with carefully tensing thier foot to get "close enough" to zero power, others (like myself) prefer to get *exactly* zero power with no input from their foot.
It is a shame to have to shift to neutral to get this however, since that can be less safe under several circumstances.
GSP