These set up flaws you guys are talking about have nothing to do with the the previous car.
Last years car couldn't turn in, visibly understeery.
This year the car chews rear tyres, on full tanks. On medium to low fuel loads the problem dissipates, so we can effectively say this is a tyre wear issue related to the rear of the car that could be solved by a more effective blown exhaust solution. Mercedes current setup works, but not well enough to catch red bull. It's not a million miles away from McLaren or ferrari either, both whom have far more complex systems.
We know that rosberg had to run 2 hard tyres during the gp. He ended up around 8 seconds adrift of Hamilton who only did 1 hard stint. So 12 laps on hards and he loses 1 second per lap and finished around 10 seconds off a Hamilton McLaren and overtook a button McLaren. Why do people not see that this is progress.