Found the time and did experiment by adding a sun. Perhaps I should view HDRI more like ambient lighting of the past and maybe those tried and tested ways of scene composition from Firefly/3Delight are not entirely a thing of the past. The difference may just be "Less is more".

As for DoF.
Been using Dof regularly but never considered it with respect to the size of the HDRI imagery. Been using it far more to bring out my figures.