Until they make this (and a native AD client), all the rhetoric around "Microsoft LOVES Linux" is empty marketing. (I understand it would be difficult to port. That's beside my point.)
Writers in our company were not very fond of Libre Office.
As an aside, opensuse is a great linux for laptops. IMHO, it has better hardware support then Ubuntu and it's a more consistent experience moving between the console and different GUI's.
What do you mean?
Slack is just not a thing for this use case, same for all the other collaborative tools. Hangouts delivers subpar video quality and decent audio quality (if we ignore the fact that it hasn't been working on Firefox for a while). Appear.in glitches and lags a lot, sometimes to the point that is not usable. Signal would be great, video and audio quality are amazing on mobile, but there's no desktop client (apart from a Chrome extension that can't really be called a desktop client). WhatsApp video quality is very poor while audio tends to be decent, but once again, no desktop client (there's an in-browser web app with no support for video calls). Skype too, is fine on desktop, but it's a huge resource hogger and consequently battery drainer on mobile (the only non-game app that manages to warm the back case of my Android phone).
So yeah, future doesn't look great. I am hoping in GNU/Ring, but who knows...