I think the aesthetics is a consideration especially if the TC is off. If you need a plain work truck/flatbed for another reason that is a different story. DW and I prefer the looks of the pickup bed as well. I also use it with a tonneau cover on it during Winter.
There are some very good looking flatbeds though, so you should be able to improve the looks over a more spartan body if you want. Either by having a fiberglass one with some curves, or painting a flatbed to match the truck paint.
As far as 19.5s go, other than not being able to air down which can't be overcome, some 19.5 tires do ride a lot better than other 19.5s. Of course, there is the added benefit of tougher sidewalls, a stronger suspension, tighter turning, better brakes of my F450 when I was choosing between a F450 and F350. Also, Sulastic hangers can also make the rear softer on a Ford. I don't know if they make similar rubber mounted spring mounted perches to make the unloaded ride better even on the stronger truck. You can also go with an air suspension.