Yes I know that, but that doesn't change the fact that although mods are awesome, they should not be the determining factor in what major -or if any at all- upgrades happen to the engine.
They are not the only reason. There are various relevant one, they are just one of them. One of the other would be the development stalling for long (see any game that did heavy changes or switched engine mid-development). In short, there are good reason for the choices made, they are in no case taken light-heartedly.
I get that full pbr would ruin mods. But reflection fresnel doesn't rely on textures so it wouldn't affect any mods. Plus this would be the PBR component with most visual result since unlike roughness maps and metal maps, the reflection fresnel will actually affect the way the car paint looks. So if any part of PBR should be considered, I think this would be it. But of course i can understand if the game engine doesn't support these changes.
