Workspace switcher and app grid have different (high resolution) scroll sensitivity
I have a smooth scrolling logitech mouse and the scroll sensitivity for the workspace switcher is too high #1338 (closed), while the sensitivity for the app drawer (and workspace indicator extension) is slightly too low #2602 (closed).
If I had to pick, I'd choose the lower sensitivity because at least that's usable. Anyhow they both should behave the same on scrolling.
Here's a weird video compilation so you get an idea. Note how the mouse reports scroll in steps of 16 at the slowest speed, which causes problems with the workspace switcher.
I don't know how gnome shell implements scrolling, but I read something about a timer. Seems backwards to me. Shouldn't scrolling correspond to scroll distance instead of time interval of scroll events? I have worked a bit with high resolution scrolling in Qt and this is what their documentation says:
Most mouse types work in steps of 15 degrees, in which case the delta value is a multiple of 120; i.e., 120 units * 1/8 = 15 degrees. However, some mice have finer-resolution wheels and send delta values that are less than 120 units (less than 15 degrees). To support this possibility, you can either cumulatively add the delta values from events until the value of 120 is reached, then scroll the widget, or you can partially scroll the widget in response to each wheel event.
So essentially you'd write scrolledWorkspaces = scrollEventValue / 120
and the remainder should be kept for later.
Tested on Arch 5.14.14, gnome shell 40.5, xorg 1.20.13.