I'm not too worried about the Stern playfields going forward. They took their lumps in 2016 for some mistakes, and I don't think they'll want to go through that again. 100% perfect yield is impossible, but they're surely going to be doing a better job now than in the past at weeding out those "seconds" from the assembly line. I do have concerns about overall build quality with the cost cutting, but that's probably more of an operator's concern than a home buyer's issue.
From people who have Aerosmith in their hands, they say that the clearcoat is noticeably improved over what Batman or Ghostbusters had. Hopefully future games on the line (even previously released games) all look as good.
While there's still good reason to be vigilant, I think that the panic stage is most likely over.