I have about 80 SM which all use the same material, and I just went through opening them one by one to assign the material. This was annoying to do. UE2 and UE3 have the same problem.
I can set some properties such as lightmass resolution on all my meshes at once, but not the material (or collision for that matter). I am looking for a way of quickly changing a material on a great number of assets at the same time.
One suggestion I have is to allow me to drag a material in the content browser onto the thumb of a mesh, to assign that material to the SM. If you have multiple SM selected or you hold some key combination while dragging, it would assign it to all selected SM/all SM you move your mouse over.
Or a right-click menu item to mass replace the material.
Or having the material slot show up in the properties of the SM.