Low priority enhancement;
Improve usability of scroll bar by increasing its width 2-3x.
Smaller scroll bars rarely have any real benefit over normal sized ones, and they cause users to slow down for a little more precision to ensure they click it before scrolling. It's a small thing, but easy fix. There is plenty of unused white space to increase the scroll bar size.
This would apply anywhere small scroll bars are used; notably website and OW app like scrolling in a long modpack list or browsing to add new mods to a pack.