This is cool. Presumably this could be implemented for other editors (vim, emacs, etc) so the language servers could be shared across editors.
Many languages already have something like this. For example, look into ENSIME, ghc-modi, and Racer. I guess the innovation here would be a common protocol for "any" language, but I somewhat doubt that this will have much adoption outside of the .NET/Typescript communities.
I agree. `vim-go` is my favorite example; it actually is comprised of a number of daemons that service different facilities. The innovation would be a common interface specification any backend can play with any frontend.