I use the Layer Shader for this kind of thing. If you right click on the word “Layers” in the shader’s properties you’ll get a pop-up menu. Select “User Interface” and then enable “Show sub-channels”. The sub-channel sliders allow you to animate, or drive, the strength of each channel in the shader. You can either drive the strength of your displacement maps with morphs directly through Xpresso, or you can set up mask channels, etc., and drive the strength of masks.
Example: 7564_morphdriveshaders.c4d.zip