Oh no, Sean's going to bang on about the Teams UI again...
Oh, yes I am.
This explains a lot.
The idea that Teams is a professional product used in diverse environments and thus requires extensive customization options is a B2B requirement.
The idea that Teams is a fun product which must be as easy to use as possible, and thus requires zero customization options is a Lifestyle requirement.
Hence the conflict.
Both of these are legitimate in their own contexts. The problem is that the Lifestyle stuff is completely swamping the B2B stuff, at least for the non-core products. SfB, Teams, and Skype 8 are big, bloated, "point-and-grunt" UIs suitable for phones, and unsuitable for desktop.
No single UI will work for both sets of requirements - we need a choice. At the very least, an "advanced options" pane with a prominent "reset all advanced options to defaults" button would help an awful lot.