Walt are you saying that Diesel electric is torque based only and not more efficient? If so I disagree. A simple Google will so this so.

Stan whether or not in it's most efficient mode the lower load will use less fuel. How much is not available to me but I arrived at this using common sense. Idle you lawn mower and try to cut the lawn verses rev it up and do some work. Which one works better? The same for the FEH ICE driving the 45KW genny is easier than the whole SUV. If Ford used a bigger motor and battery pack we most likely could have the gas electric all electric SUV in stead of what we have now. I think cost was the over riding factor hence what we have now. All speculation on my part but I see a small efficient Diesel driving a generator which runs the electric motor as being something worth looking into. You would use the battery pack to add power for starts and hills and passing. Otherwise the genny would power the motor. Not new just different and perhaps better.

Since Ford is already installing the ICE in non FEH it makes better $$$$ sense to modify what they already have and thus what we end up with.

Starting with a clean sheet of paper could have given us an even better product but cost keeps all things in check.

One last point run the ICE at it's best and worst case of FE and I bet it is not that big of a difference as in either case the ICE is very inefficient compared to the electric motor.