There's actually a lot of code involved in checking if all textures use
the same transform or coordinate set, especially when considering all
fallback variants and potential future expansion with separate texture
offset/scale/rotation attributes.
A lot of the complexity was thus hidden in plugin implementations, which
were each trying to find a common value for all textures to save the
user from doing the same. All that code can now be removed and left up
to the material APIs themselves -- now it's just about checking
hasCommonTextureTransformation() and then retrieving that one common
transformation, independently on how the material actually defines it.