That is the inevitable. BMW and Merc (and Lexus/Toyota) have a history for hand-me-down styling from the top ranges to the 'lower' classes. Merc: All the gadgets and creature comforts as well as the styling that were only to be found in the S-class, went down to the E-class and today all the poor-man's Merc, the C-class have it. Same goes for the BMW from 7 to 5 to 3.
But IMO, the best example of this is to be found on the Lexus IS300 and 250. By far a looker, but today you have to squint to see the difference between the new Corolla and a IS. THAT in itself I think really knocks the resale value of a Lesus IS. It doesn't stand out anymore...
So fire the BMW designers (or allow to step down...), but there is little the guy on the street is going to do to immediately affect the styling of tomorrow's BMW. :nono: