How great would it be to have the ability to create Aliases (or Instances) of Layers?
These Layers (with the name Italized) should dynamically reflect the exact RGBA content of their original.
Would save a lot of copying, expressions etc. And would be a nice hybrid of node based and layer based compositing.
Constantin Maier commented
What you can do: Create a solid at comp size and add the "Calculations" effect. Select your desired layer, set it to reference "Effects & Masks", dial the opacity to 100%, and change the "Blending Mode" to "Copy". If the layer has Collapse Transformation/Continuous Rasterization, transforms will be referenced correctly. If not, your solid needs to have the dimensions of the referenced layer and you would still have to link transforms using expressions as well as the parent. However, if you add effects/masks to the referenced layer, everything will be updated automatically.
If you're interested, I created a script that offers various ways to clone layers: https://aescripts.com/workflower/
"Clone & Precomp" will duplicate your layer and link it via expressions. If you change non-linkable attributes, the script offers the ability to refresh the connections.
That being said, it would be great if AE had that feature natively. (Although, I guess considering how much time I spent on my script, I must now hope, they don't do it. :D)