The 2007 UI was a major step backward in term of productivity. Everyone I know who uses Office extensively still miss the 2003 UI.
Also there are lots of use cases that they never bothered fixing or improving, which show they don't really use it. Like non resizable windows in excel (eg function wizard). Linking a powerpoint deck to an excel model (no good solution now). No way to do placeholders within a textbox in powerpoint (like you can in word). VBA not having evolved in nearly 20 years. You don't see this sort of "I don't give a shit" attitude with Visual Studio.
I am sure someone in the finance or marketing department at Microsoft uses office and is as frustrated as every other power user. But the developers in the office team clearly do not use their own product. If there are still any dev in the office team. The only changes I see from version to version are purely cosmetic.
Pretty much everyone I know likes the Ribbon UI, you don't have to drill down in nearly as much menus. Granted, it only really started to get better after 2011, but its excellent now. There's a reason there's such a huge pressure on LibreOffice to come with some kind of interface paradigm that doesn't feel like it's from the 90s.
My main and continuing complaint with the Ribbon is that using it is slow. It encourages mouse usage and if you have to use a mouse for an operation, the operation is slow.
Not to mention that the action of the Ribbon is kind of seizure inducing as the entire thing is in constant change as various objects are selected thereby unhiding specialized menus.
I've taken to minimizing the entire Ribbon so I don't have to see it, requiring me to re-learn and re-memorize the multi-key keyboard shortcuts since they are different than the 2003 version.
