BTW the A-pillars have a regulation requirement that goes back to the original '66 FMVSS NHTSA safety standards. It requires that the A-pillars do not block the vision of the driver so one can see pedestrians at a crosswalk in both directions. I think that is one of the reasons the '68/'69 B-bodies for instance were different (dash/windshield) in distance and layout to the driver's forward vision. The smaller or thinner the A-pillars are for increased pedestrian and bicycle sighting the less strength is has for the roof crush regulation and the more need for a B-pillar. Ironically the B-pillars also reduce vision or sighting ability of objects and pedestrians. Car design has so many regulations, and limits now that what's cool and better "looking" most likely will not be the same as a no B-pillar concept or show car and not go into production.