Just my thoughts regarding the reason for the playfield issues: could it be that the reason might be the ball itself, especially due to airballs, which crashes on the inserts and makes the cc lose. I know that as main reason the different movement of plastic insert and wooden playfield is stated, but that alone does not explain why the cc gets chips in the shooterlane (where no plastic is) and why there are comparatively low damages already out of the box.
So as a consequence, if the ball play itself causes the cc damages, a plastic playfield protector should prevent the ghosting. I do not see which machines have such protectors, but it would be interesting, if anybody has damages despite a playfield protector.