Not sure the Pagoda would make a nice Pick-up
(but the W111 Coupe would, by moving the C pillar on top of the B pillar and have the back of the side widow rounded to match it !)
I find the original design very nice, and I don't really see any possible improvement. May be the back top angle of the side windows which is a bit too pronounced with the soft top up. But then I don't see how a rounder window would fit with the design of the very specific hard top. Or the back top area could come closer to the back seats, and it could be flat, ala thunderbird. This could give a better flow to the design with the top down.
At one point Bracq tried to convince MB management to go with horizontal headlights, at the time of the W108 I think. This could have yielded a facelift on Pagodas prefiguring the r107. I wonder what the car would have looked like?
Frua tried made it into a shooting brake, not sure the result is better thn the original. May be Paul Bracq could have a go at it ?