That's probably why the Daily with a higher payload capacity than the Ducato/Promaster has RWD.
On the other hand the FWD layout has many advantages compared to RWD: Better in snow when not heavily loaded (and more predictable under- than oversteer), reduced drivetrain losses, reduced weight, increased cargo-volume capacity and reduced cargo-area height which is why it is often used as a car transporter/tow-truck in Europe:
Also, the missing center console allows 3 people sitting in the front.
(I agree that the Ducato is not a pretty car, but it's supposed to be practical and not sexy).
The only non-turbocharged diesel-powered trucks I've seen around here are these designed in 1959 and the only reason why it didn't come with a turbocharger was because the military doubted its reliability back then:
https://en.wikipedia.org/wiki/Saurer_2DM
I'm not sure about the aero-drag of a Ducato, but a flatter nose has at least the potential of generating less drag compared to a long nose with a shorter back end:
Audi A2 1.2 TDI technical details, history, photos on Better Parts LTD