Why would you assume that the 6 series would follow designs of previous generations BMWs? No modern BMW looks like previous generations. The 6 series does have a continuous design theme but you're never going to find it if you're looking for it with designs of the past. I'm not sure why you would want to backhand Adrian Van Hooydonk either. He's an extremely talented designer (what are your credentials in design?) who now happens to be in charge of the entire BMW brand's design. Apparently, BMW's boardmembers or sales figure don't follow your thinking.

Now I would like to talk about this "definitive proportions and inherent balance that exsisted w/ both the E24 & E31" you mentioned as these two models share little to no design themes or proportions.

E24- it's "definitive" proportion was in accordance with the BMW design of that era, boxy. Look at the E30. It shares a similar appearance with the upright and tall driver's greenhouse and its flat hood, sides and trunk. With the next iteration of BMWs, the greenhouse and overall shape became less obtrusive and more streamlined, look at a E36.

here's an E30 for comparison with the E24


E31 - this car follows the an extremely generic coupe shape. It could be mistaken for a Pontiac Firebird or any late 90's coupe like that. Perhaps generic is what you were expecting from a company that once gave customers just that, simple designs themes that carried across generations of cars, like Porsche. That was BMW of old, not BMW today.