> Cause we can siphon from the huge man-hours of development and polish that M$ has put on VSCode.

Anything done on the language server side is already coc/built-in client agnostic (since communication is done over json-rpc, except for tsserver which MS has not yet exposed via the LSP, so we rely on the typescript-language-server-wrapper), anything on the client side is marginally useful at best.