Absolutely agree. It is good to keep talking about these topics though, to highlight that they are still important.
Some things that would massively increase the number of possibilities for Cycles materials would be the aforementioned loop node. But also a generalised shader math node (we have add and mix, but subtract, multiply etc would greatly increase the range of possibilities).
I did have a solution for shader subtraction a few years ago and got some very interesting results - unfortunately, recent updates to blender mean that solution no longer works.