I think you are right, in that the reveal brush doesn't actually paint much of the procedural texture except a rough color approximation. Sorry for that misinformation. I had tried revealing a shader with a texture map and it worked. So I don't think right now you can reveal anything but the color information of a shader. You can copy those maps over to other channels, like bump. But that's about it. I'll have to bug the developers to add that, it seems possible to me. Of course you can paint those other channels by hand, also if you like.