Small update.
I have been playing some more (see GIFs below)
As it stands, its 95% working with all nodes (built in and contrib) (small bug on template node not remembering value upon editsave - but I've probably missed a proxy)
NOTE: none of the nodes were edited to make this work (only editor.js)
function node (demonstrating jsdoc abilities)...
change node - json + buffer (demonstrating sub editor works too)...
template (demonstrating excellent CSS intelliense)...
Still not sure where I will end up with this but i'm enjoying the playtime & challenge.
