Hello!
What spoils the ‘user experience’ a lot when using the material list ist that the textures need to be loaded first before the list is shown. With huge textures, this can result in a substancial lag.
How about: the list pops up immediately without texture preview on the thumbnails, then the textures load in the background, and the thumbnails update, one after the other, which can take as long as it takes then.
The thumbnail preview is less relevant when choosing a material - the name is sufficent.
Thanks!