We think we can make a few improvements to how scrollbars look and work.
In Blender 2.8, we made it so scrollbars don't make the content jump around as they appear and disappear. However, to do this, scrollbars had to be made very thin.
We would like to make the scrollbars just a tad wider:
This requires creating a little bit of extra space always, so scrollbars have enough space to appear & disappear inside this gutter area.
We can also use this opportunity to unify scrollbars. Currently, list view scrollbars are huge, while the regular 2D view scrollbars are very thin. Here, both are unified:
It's also desirable to keep the scrollbars always visible, rather than making the fade away completely. This makes them more practical for use with devices with no hover state (some tablets), and also for users to see at a glance where in a list they are.
We can keep these at a very low opacity. When the cursor is close, we can then make them much more prominent: