I like it the way it is, it works very well for me. And for beginners; if you add a surface layer you immediately notice that it's covering the base layers with a white color. If you don't need that color, switch it off. Then you are free to add children layers and stuff with their own restraints, and use that surface layer basically as a 'container'. If you need a color there, get to work on the restraints for the desired effect of that color on the underlying terrain.
I'm not waiting for too many nodes, and that makes it even harder for newbies to choose what to use. Of course, many nodes could have a masking input (displacement, vector displacement, distance, simple shape....), but I don't think they really should all have them, as they can just be used as children on a surface shader (as container), which has that mask input.