I have a 2011 e90 and have zero dust. I can go a month without worrying about dust. I was told that the 2011 cars have a new pad formulation. The original OP must have had these same pads on his new car.
Suggest you go right back to the dealer and demand they replace them with the same new formulation pads. As someone else suggested, they clearly replaced your pads with older stock. The difference is not minor, it is night and day.
Koni sport, BMW performance springs, M3 arms and sways front and rear, M3 subframe bushings, Velocity toe arms, M3 front strut bar, Cobb, ETS FMIC, Vishnu charge pipe, RPI scoops, M3 steering wheel, City Vision angels, CDV delete, Advan RS 18 inch, Pilot SS