Would it be possible to copy/paste the different textures between the different slots? I use a lot of same bump-maps in the reflections slots and a lot of diffuse maps in the translucent slots for example.
And also interesting would be to be able to copy paste materials, sometimes you have models divided in a lot of different materials even if they actually could use only 2 or 3. If you could copy/paste materials this would make it much easier.
Also the ability to rename the materials after having edited them would be great.