I never know which of the inputs is zero and which is 1
Something like this would make it easier…
Imo this would clutter the Node UI.
It took some time to get used to but it feels quite natural now
It’s like when you plug an usb key to your computer… always the wrong sense, you have to turn it up 
It’s the mix factor for the bottom one. Always. You only need to learn this once.
Yeah I can see the value in having something like this.
it’s not clear which end of the factor is represented by which shader. In my opinion this is confusing UI design.
yes most people can learn this or get used to it but what if you’re a newby or like me, an infrequent user who has to re-learn this when revisiting node set-ups.
Node networks are great for experimentation and flexibility but their low level building blocks should, if possible, be obvious and unambiguous to use.
If a pedestrian crossing provided indistinguishable signs for “walk” and “don’t walk”, would you want to learn the difference by trial and error?
It is obvious and unambiguous
If a pedestrian crossing provided indistinguishable signs for “walk” and “don’t walk”, would you want to learn the difference by trial and error?
If it did not potentially cause death, then yes. Death by computer programs is something which is nonexisitant. Learn by trial and error in computer programs is one of the most efficient methods of learning.
Not for everyone or at least the uninitiated. If it was then the OP wouldn’t be making the suggestion.
If it did not potentially cause death, then yes. Death by computer programs is something which is nonexisitant. Learn by trial and error in computer programs is one of the most efficient methods of learning.
Yes and pedestrian crossing don’t cause bad node set-ups. I’m partial to occasional colourful metaphors y’know. 
Trial and error is one of the cornerstones of the human learning experience but sometimes it’s unnecessary when stuff can just be labelled or marked up.
yeah, Its like when a car does not indicate which side the fuel door is on,
inside,
sure you figure it out eventually,
but proper labeling spares you this.
No, it’s more like the car not indicating which side the gas/brake pedal is on. You learn it once, and then it’s always that way forever.
Yes, this.
Once and done - Blender uses top to bottom mixing in every portion of its interface - material editors, texture stack, paint layers in 3d Texture paint, node windows for materials and compositing - only exception I have found is the VSE channels.
I actually think black dot connect point, white dot,
changing the slider changes the color of a little bar?
0 =1,1,1 white
.5=.75,.75.75
1 = .5,.5,.5
but this is just my opinion.
That’s a pretty good idea, but it might run afoul of the ability to scale the node. Might be simpler to right justify the ‘shader’ on the bottom, so it’s associated visually with the right end of the slider.
(White dot, well, light gray, already has a meaning in the node socket color code. light and dark green might work.)
How about a coloured ring around the socket associated with the end of the slider?
What about renaming the top shader input “Base Shader” and the bottom shader input “Mix Shader”? Text changes (not text placement changes, actual changes of text) are almost always the easiest for a coder to make.
Well, even when i was a complete beginner with cycles and blender in general it was pretty simple and straight forward how the node worked and which value was which input. I don’t see any reason to change the design, as for non-very-beginner users it would just become visually annoying.
I think it’s an interesting idea but not necessary, and probably it would take a ridiculous amount of time to code than it would ever save anyone 
I am also suspecting this thread will get out of hand because everyone understands mix-nodes.
What about a helpful little fella’ in the bottom right corner that gives you helpful hints like “It looks like you are trying to mix two shaders! Let me help you”. Something like… a paper clip!
Just learn it’s about reading order: top to bottom, left to right - zero to one.
And never be confused again.
Or in the case of Blender bottom to top Think of it as the your typical 2D programs layer stack but inverted. So your top most socket is your background layer and the bottom on is whose opacity you are controlling.