The current design has a few shortcomes:
- It sets itself apart from Cycles
- It leads to ambiguity when dealing with multi-engine materials
- If we have a Specular, a Metallness and a Cycles Output material node, and the Cycles is the active one it's not clear which Eevee node to use as output
So the proposal is to create a new node for Material Outputs in Eevee, and turn the existent nodes into "shader" nodes, exporting "closures" (the green outputs) into the Material output.