Does a lower profile tow better? NOT a mileage Question

Much of the drag that reduces MPG comes from the flat shape on the rear of the trailer. You can divide the air on the front any way that you want, but it needs to come back together at the rear. Did you ever see a sub-sonic aircraft that wasn’t designed in a way to best bring the air flow back to center? Making fancy designs out of the trailer front might even make things worse if the pressure wave is directed farther out, but it sells trailers.