When you're working in Rhino there is really no advantage to having vectors rather than the pen viewport. All of your linework is turned into pixels by your screen, which until we're all working on 16K screens, the pen viewport is just as good at. It would be good if there could be a pen like viewport that would accurately scale line weights when zooming in a layout, rather than just being 1 or 2 pixels wide. Vectors are really only important when exporting or printing, so maybe it is like @Holo suggested where a Make2D processes slowly in the background while you make changes or maybe it just calculates when you export. It could make for a slow export, but it would give you what you need.
I also think that in the absence of a real-time Make2D, it would be very helpful to be able to run a Make2D to a separate file in the background. If there's a way to capture all of my geometry as it is now, export it, and run Make2D calculations while I work on other parts of my file, then with a little planning I can really improve my efficiency. My biggest problem is that when I'm running a Make2D, I can't work on the rest of my file.