We provide a client, not language servers, so we're kinda at the mercy of whatever language servers exist. We offer a configuration in lspconfig for https://github.com/theia-ide/typescript-language-server which wraps tsserver, but there is hope that microsoft could implement lsp protocol directly for tsserver https://github.com/microsoft/TypeScript/issues/39459#issueco... at which point the experience should be more comparable to coc.nvim.
On a different note, we have made upstream requests to MS, worked with language server authors, and generally try to contribute positively to the language server ecosystem. Neovim users will always be free to use coc.
If you have actionable items for improving the client, please reach out on our discourse or on our matrix channel. Thanks!