To summarize, the problem is that Blender’s tool system is too duplicated. A lot.
There are mainly two issues:
These adjust last operation(redo last) discussions are also because of tool duplication. This wouldn’t be the problem if the edit actions(such as bevel, extrude, inset, etc)were properly implemented to the 2.80 tool system. They(hotkey actions such as B, E) still use the operator, not the new tool system. If the action needs adjustments and sliders, it should use the tool system, not the operator and adjust last operation. Some tasks(such as save all images) are better suited for operators, but many others(which needs options and sliders) are better suited for the new tool system. I agree that adjust last operation is not the right thing to exist in Blender. It’s a funny thing.
On the other hand, the tool system has too much settings duplicated over the UI. A good program shoud provide one elegant way to get the job done, not many confusing ways asking the user to choose one of them on every task. (This is also the motto of Python, which makes it a beloved programming language)