Current status: 94/150 supporters
As soon as you remove the barrel distortion they are gone, a little homework on the camera will tell you a lot about the camera. LEICA User form for instance;)
The barrel distortion seems to be pretty pronounced. The lens could be designed with the premise of the digital correction.
Yes, it is very pronounced. Correct it in post and the vignetting is gone.
The recent incarnation of Photo Ninja deals easily with the Leica Q DNG format as such. However, one has to do a manual distortion correction if it is desired to get rid of the dark corners.
Better solution than a hacksaw!