Moving the VSE content out of scene data structure would allow for much better integration into the various editors including the compositor since it would make it possible to access the current scene in scene strips(which was possible up to 2.79) and thereby avoid the problems of recursion(both in and out of the sequencer and compositor). So, for me, this is a superior solution. Suggestion: Make the Sequencer contents into data-block, which can override the switched to Scene-Sequencer contents And solving the slow speeds of scene strips should be prioritized over any node work, imo, since it is already possible to get compositor output into the sequencer that way: The poorly exposed Scene Strip properties, which results in bad UX:
Currently, there are already UIs for effect strips and UIs for modifiers, adding a UI for basically the same functions in a node editor(but add similarity to Resolve workflow), would just result in more UI clutter(though nodes are nicer than strips(but adds Afx like workflow) and modifiers(but adds similarity to 3d workflow)).
An alternative way to get strips in and out of the compositor could be as movie-clip-data-blocks. If the VSE had the option to convert imported a/v material into movie clip/sounds/image data-blocks(add on for this: Convert selected strips to assets via sound, image or clip IDs. · GitHub) Using the movie clip node ex. the movie clip data-block(source file) can already be imported into the compositor, so what’s missing is storing in and out points of the movie/image data-blocks from the strips and reading this into the node, and then a data-block output node would be needed. This way the source strip could be round-tripped in the compositor and returned into the movie strip(with an option to select the compositor-data-block output instead of the source-a/v material).
Converting a/v material to data-blocks will also have the advantages of the Asset Browser and the Outliner will be able to show these files and users can tag, organize and drag & drop them into the sequencer: