I wish we would have the equivalent of the language servers but for collaborative editing. That way you could edit with one user in emacs, one in vscode, one in intellij etc.
And if you can make Emacs and vim users happy then you can have world peace.
The only problem we had with it, was that it was only 99% reliable... And that 1% error (in the connections dropping and such) was annoying.
But I still consider floobits a project with great potential.