Assuming that the whole physical linkage is re-thought.
I'm with LarJ, getting the trailer to push would be a pain in the tailpipe.
Although using the breaking in the trailer to recapture the energy is a really good idea.
Ideally the same amount of energy is recaptured, and the same amount of energy is required to get things moving whether the power comes from a centralized transmission or is distributed.
In fact, I think that's what they do with locomotive trains.