TL;DR
Replace "Red Wire" and "Green Wire" with "data cable," allow setting channels for signals as colours.What ?
Circuits are often difficult to visually read in combinator layouts, and anything that requires multiple inventory signals can require vast amounts of combinators.I have in the past proposed adding more than just red and green, but I appreciate this adds much more complexity, especially to the visual reading of things, and increases the number of wire connections needed on the graphics.
A simpler and perhaps more comprehensible solution, allowing for better combinator functionality, would be to replace the two types of cable with a single data cable. Red, Green, or additional channels could be selected at device level.
Devices with multiple functions, such as inserters, could have different functions assigned to different network addresses, making, eg "hand contents" and "set filter" possible on the same inserter without the use of multiple combinators per inserter. Combinators could have inputs and outputs set to different channels, to enable for eg "each red" / "each green" on arithmetic combinators or "each red" < "each green" output "each purple" on deciders, for a way of saying "which items are under a specified level" or something like that.