, the biggest problem is the number of ships I have to convert and how they work.
There is a loss of spec maps, which are way too much work to convert to PBR maps.
Here is an example
Probert Ambassador and C in different exposure modes
Viewed from the bottom in auto exposure
So without proper PBR maps and just using engine basic PBR for roughness/metallic you gain a more realistic shine and environmental wrapping, but lose the hull plating and specular shine.
As far as I know, specular map support is not supported for PBR