It seems there are still divided views about overtaking in 2017 even by engineers from the same team. Red Bull’s chief technical officer Adrian Newey believes there will be less, but Red Bulls chief engineer Paul Monaghan believes there will be more. It will be hard to judge by numbers alone as Manor who were overtaken a lot will not be on the grid and it is expected that there will be fewer pit-stops.
It seems that it will depend if the 25% extra grip from the tyres will overcome the increased down-force, Pirelli also claim the tyres will be more durable so cars should be able to do far more laps than the tyres designed to degrade that we have had to suffer over the last few years. Also it must be remembered that more down-force means more drag, so if cars can manage to get into the slipstream of the car in front overtaking could be easier, but the larger tyres will reduce braking distance. There is also DRS, what effect will bigger wings have on DRS, it should give following cars even more speed. The cars should be faster so it is impossible to know if this will force drivers to make more mistakes.
Not long to go, I don't think we will learn much about overtaking from testing, I guess we will have to wait until Melbourne to see what effect the changes have in the real world, if Engineers and drivers differ on the issue, racing will be the only way to sort it out.