There are 1001 different ways to style the wires. The fact remains that in the flow definition the wires have no properties. All the flow definition states is NodeX is wired to NodeY.
Any proposal that involves additional 'nodes' along the wire will mean a change to how wires are defined in the flow json. That is not a minor undertaking and would make it impossible to import flows between versions of NR that did/did not support.
There are other (more functional) reasons why we may consider allowing wires to have properties in the future, but it isn't something we're looking at today.
