CMT for concurrency + DLP for parallelism is a he'll of a lot more scalable in LOC than the unsafe hammer of preemptive. We keep unsafe parallelism to only tiny tiny tiny GPU code snippets.

Node's concurrency and parallelism probs don't require deep lang changes but runtime ones and some ergonomics to be closer to Go -- and not far IMO bc of last few years of work for Async, safe (fresh env) eval, and json/buffer msg's.

More exciting would be something like Apache Arrow / Berkeley's 'Plasma', but that stuff is still more exploratory.