I agree with you. The ribbons don't suitable to a small screen laptop. But several palettes that showed simultaneously don't suitable too. I haven't ready-made solution, but I think the user interface have to develop.

The code shows great promise. Thanks, I am going to try this!

You can create ribbon toolbar based on DockedCells and TabView and other ui elements.

Then you can move Default.nb to appropriate place in $UserBaseDirectory and make this DockedCell a default one. See General approach to modifying built in stylesheets to get an idea.

If you want to add new items in menu bar / Edit or anywhere, copy MenuSetup.tr to analogous dir in $UserBaseDirectory and edit it accordingly. See this topic https://mathematica.stackexchange.com/a/109396/5478 where I created an additional menu to quickly open important directories.

I'm not 100% this answers your question so sorry if I missed the point.

p.s. about stagnation in GUI updates, yes, we are victims of a need to keep things consistent across Mac/Win/Linux and now also web FrontEnd as well as iOS.

So, you would prefer that (for example) the edit bar (formatting option for the top of notebooks) be expanded to cover the options currently in the Writing assistant palette? I think this is a useful idea. Right now, the option is a very simple form of the ribbons, etc., available in most word processors, although the ones in Word are way too complicated for the more modest needs of a notebook.

I have the same issues with palettes obscuring notebooks, etc. especially when I use my laptop. The UI is functional, but dated, as you say. The classroom assistant, and other palettes derived from them seem to be unchanged from 2008 when they were introduces, and the widgets in them are not really aesthetically pleasing. No criticism of the developer -- the functionality of the palettes is excellent -- but the UI elements are, in general, not very pretty. This may be due to the fact that their metrics, if not appearance has to work across Linux, Windows, and macOS. The equivalent format pane in the On-line version of Mathematica may be a step in the right direction.

To the contrary, I utterly hate and detest the ribbon toolbars in MS apps.

Palettes in Mathematica can stay where you put them. I love the decoupling between the separate palettes and the main work areas, namely, the notebook windows. to say that positioning them takes more time than using them is utterly absurd.

The "interface", contrary to what you claim, is much more friendly with practically each new release. For example, the pop-ups for possible autocompletion, with quick links to help or templates to paste, are very helpful, for beginners and experienced users alike.