[pencilhappen]

Node is adequate at async, but not excellent. As I said in a sibling comment, things that are synchronous still, like GC, make it fall down at scale. Isomorphic JS isn't that useful in most real situations.

My point about Scala is that there doesn't seem to be a clear cut niche that it excels at. There are numerous other non-Java languages that run on the JVM that could be in the running, and they all get to take advantages of the whole Java ecosystem too.