The more I see these bargeboard evolutions the more I see where Mercedes went wrong. Well not wrong, the thing stopping them from having the superiority they previously enjoyed. I expect to see the chassis take a big step forward next year, I just hope the chassis complexity doesn't hamper their development. Where Mercedes can make big gains is in the sidepod areas(Ferrari is ahead of the curve and their chassis shows), I expect Mercedes and most teams really to try and copy that elegant solution. It's clear all the developments are attempting to manage airflow creating a high pressure zone at the sidepod undercut. This creates not only downforce in that area of the car, but also increases both speed and mass flow under the car increasing diffuser efficiency.
It's why you see small diffuser like tips at the edge of the floor running along the side of the car.