I use V-Ray 7 for SketchUp and I find the new material preview thumbnails significantly less useful than the previous presentation.
Previously, I could quickly identify whether a glass material was transparent, smoked, textured or opaque by looking at its preview. With the current thumbnails, these differences are often difficult or impossible to distinguish without importing the material and inspecting its settings.
This adds unnecessary steps to the material selection process, particularly when working on detailed interior design projects with many different glass, stone and other material finishes.
My suggestion: Please introduce an option to switch between the current thumbnails and the classic material preview style, or improve the previews so that transparency and other key material properties are immediately visible.
The previous presentation was more practical for professional workflows. Please consider bringing back this functionality as an optional setting.