McLaren have always had a very stiff car for 3 years now, not convinced a bumpy track is going to make a difference. None of them are that bumpy anyway, there race tracks, not roads.
And I don't buy that McLaren with all their racing heritage designed a car that dislikes bumps, thats a real disservice to the team.
I understand that the bumps are a problem, because the aero is hyper-sensitive and will only work with a very specific ride-height.
The aero itself is clearly deficient, otherwise they wouldn't have been able to bring improvements by taking a hacksaw to aero parts.
Now they've had time to analyse the problem, I will be very disappointed if we don't see a big improvement in China. But for the car to work as intended, we may have to wait a while.