I feel this would be a huge benefit; to have specific node setups that only output to Verge; so I can have other node outputs that are used strictly for EEVEE or Cycles. In the current material ‘output’ node; it is set to ‘All’ by default. but you can select the drop down menu and change it to only be used for either engine.
Allowing the same behavior for Verge3D materials would be very liberating.
Another thing I have asked for in the past; is a way to flag certain nodes that do not generate usable data to Verge3D. It could be as simple as clicking a button on the header of the node editor that would put a red outline around nodes that are not recognized by the Verge3D engine. This would be so helpful in trouble shooting problematic materials. And at the rate new nodes are released; this seems like the most reasonable approach to quickly determine what is or is not working.