I've tried to do the same thing: going completely text mode. For me, it was disastrous -- it was a big distraction for me at work, at two jobs. I even left a good job partially so that I could try to go text-mode rather than click my way through lots of GUIs. It was something of an obsession. Now I look back and sigh.
I’ve recently rediscovered emacs and now use it as my primary tool for development. I already loved working in the terminal for git and xcodebuild so it’s felt natural.
Moving editing and workflow into emacs has been great so far. I’m already customizing things. Even using eshell! Excited to look into other things like a music player or email app. Or even slack like the author: https://github.com/yuya373/emacs-slack
Okay, someone built an emacs plugin for slack[1], it doesn't look like a very usable version of slack, but I'm pretty sure it'd be quite possible to fix this up a bit, prettify the UI, and end up with a much more performant version.
Slack APIs aren't perfect, but they're good enough to allow 3rd party clients for terminals, Emacs[0], and the like. I've never dug into it because I avoid Slack in general, but I think the biggest hurdle right now is just user authentication.
That's a pain, and does limit your audience, but maybe you'd still find some buyers on HN.
I was semi-serious, semi-joking about how wonderful it'd be for everyone on a team to use emacs. It really is the best editor in existence, and it really is usable by anyone, not just developers. And it integrates with git[0], GitHub[1], Slack[2] &c. too!