"What if the setup were really more like a diesel electric locomotive, with the addition of the battery pack to recapture waste energy, from regenerative braking and/or periods of low power demand, such as idling or descending a grade?"
The problem is how do you store all the energy, not that it isn't possible. There is a tremedous amount of energy to be stored in a loaded truck going downhill.
Diesel Electric would not be practical for a truck, I don't think. It works for trains because of the matter of scale and that the torque curve to get a train moving is more suitable for an electric motor......among other things.
I am skeptical of a hybrid truck, not sure a diesel electric truck would be even practical. need more data....
It would make the use of a smaller displacement diesel engine practical, and fuel tanks could be smaller for comparable range, so some or all of the weight from the battery pack might be offset. Still, since this will be a bespoke design, they'll be looking for weight savings wherever practical and cost effective.. The article referred to "dual mode," so a combination of direct drive and a "reservoir" of recaptured waste energy is what they're talking about, electric assist from reserves in the battery pack for initial acceleration and hills, via computerized sensors of some kind.