I’m currently using LibreOffice with the menu, tool bar and site bar. That’s the usual interface within the stable mode. I played around a bit with the experimental mode and the new user interface. The functions are organized in menu band yet, but you could also use the current interface in different flavor. I started my play with the tool bar standard and changed over to the compact version of it. Then I activated the site bar. This were the first three views.
Then I changed over to context dependent grouped tool bar and the same in compact mode. This were the user interface style four and five. The next mode shows the tool bar in regster. This view is also available in a compact mode. I got tool bar style six and seven. And then I activated the grouped mode for the tool bar, which is available in compact mode too. Thus I had played around with at least nine different user interface styles. I could top up this with the option to show or hide the menu bar.
I imagine the question of user to the user support about a feature of the office suite, when they first have to sort out which of the different views / UI is activated at the users desk.
It’s great to improve the user interface and match it to the current technical expertise, but it’s not appropriate to delight the users with up to nine different versions of the user interface. Maybe one option would be to deliver one new UI and create one or more LibreOffice extensions with the other UI options.
But maybe the UI of the future has to be developed in diffent way, using Java Script, Angular or something similar and make it more easy to run the office suite on different platforms, different desktop environments, operating systems, mobile devices, in the cloud / browser.