Just upgraded to Office 2016 and its not that much different from office 2011!
I have used both for the past 6 years or so, and 2016 is significantly different than 2011, it looks and feels much more like the Windoze (2016\O365) version than 2011 did.
At work we run Office 2010 for Windows 7 and these Mac versions just cannot compare to Windows.
For most users, the Mac version compares very well to the Windoze version, granted there are advanced users who will notice a handful of features missing, voting, recall, etc. But these are not features average users use everyday. Most plugins are missing on Mac as well, but then most plugins are third party. I recall seeing that better plugin support on Mac is coming. I also recall seeing O365 Mac versions are closing some of the gaps.
Why do 99.9% of corporations in america run Windows? Is it because of a lack of features on the Mac?
Because 99.9% of corporations are stuck in the thinking that Macs are foreign to their workers, or simply don't appreciate the benefits of offering Macs to their staff. IT generally lacks Mac expertise and Windoze admins are a dime a dozen. I could go on, but many large IT shops are starting to recognize Macs in the Enterprise are a good fit.
As others have pointed out, MS would obviously prefer consumers buy Windoze, MS Office, and MS backend solutions, or that buyers go the Office subscription route. They do understand that there are about 10-15% out there who prefer Mac and that is large enough to make a Mac version (plus it keeps anti-trust regulators at bay). They now also offer Mac versions of Dev tools as well, so they get it and are reluctantly giving what the marketplace demands.
Longtime Mac users understand this second class status and live with it given the other benefits macOS affords them, not least of which being the office Rebel (a badge worn with pride). I find that aside from second class status from MS, most apps are either equal to, or more feature rich on Macs. I keep my company provided PC for the once every month or two times when I need the missing features or apps. By far, the most common task on my PC are loading security patches and rebooting it.