Thank you for asking that question in the way you did :)
Honestly, I still use the same Beer's law formula approach when I'm doing this kind of absorptoin material where the thickness affects the color. While we have volumetric shaders included in 2.79 which is a more physically correct solution, I find them slower and less controllable than the beer's law method presented in this course/video. I keep it as a custom node group that's in the startup file so it's always available when I need it without having to re-create that confusing string of math nodes.
I really can't think of something else I'd change with 2.79. OH except for the Texture Slots. That changes the way we have to setup painting in the viewport. But not really a process change as much as a UI tweak.