I was told by some nice users that I also should post my wishes in the request thread.
Before I post a new thread for every request I have I think its better to gather all of them here

If you think its better if every feature has its own request thread please tell me so!
For further info: I work with Cindigo aka Indigo for Cinema 4D

The following list is priority based. Of course I only can talk for myself and my workflow

Layer shader: (for textures and other ISL shaders) Like in Photoshop. Where you can place textures / shaders on top of each other. Set their transparency and or mix them with mixing methods like add, multiply etc.
If it was to difficult to built a layer shader than at least a mix / blend shader. As in a blend material you have shader / texture slot A and shader / texture slot B and a mix value that also can be replaced with a texture or a shader.
A ramp shader: A shader where you can remap brightens and colors of a input bitmap or shader based on a ramp / curve. C4D users know what I´m talking about (Colorizer / Filter Shader). This is what I use inside the shaders the most. Just to fine tune the look of a bitmap or another shader I have loaded in.
Dirt / Ambient Occlusion shader: (with a invert normal option): Especially with the invert normals option you are able to create worn edges and all sorts of aging effects. This would also greatly benefit from a layer shader as you could multiply the dirt with a texture to get more uneven / organic results. I do stuff like this in other engines all the time.
Support for Vertex Maps: This is another way to create more organic looking textures. You for example can mix two textures based on a vertex map. It really comes in handy from time to time.
Anisotropic Reflektions / Spec: This seems to be in development as I have seen in some posts from the devs. I just want to underline that I really appreciate this feature.
This concludes my list for now.
P.s. some really awesome users already gave me some tips how to achieve some of those effects which is really nice. However I think it will definitely improve the workflow to have some if not all shaders included into Indigo.
Cheers,
Raphael