Yep, that pretty much covers it.
You don't need a special shader. In fact it would be better to edit all specular maps. We're just taking the easy way.
As far as the visual difference goes:
This is the old ambient light system:
This is a shot without ambient lighting (and no emissive light either), but with a diffusely convolved cube map:
I'd recomend waiting for the material system before you use it though.
You loose all sharp reflections and you'll probably have to edit most if not all specular maps.
On the plus side, it doesn't cost any performance and it doesn't kill the normal maps anymore, like the ambient light does.
