I doubt that I would ever own a Stern, let alone a NIB Stern, but any new playfield that is ghosting is not a good thing.
I would expect anything that I purchase *new* to be just as they advertise. It should match the pictures/description of what they show of the product.
Now after some time passes, I understand that use and even the environment itself will cause changes. Those things will vary from machine to machine. A manufacturer that is known for problems that develop after time will have that tied to their name for a long time. And eventually, it will come back to haunt them.
The only machine I'm considering buying NIB would be the next Elvira machine. If Stern is building it...then I'll have to re-evaluate that decision.