The ability to vertically & horizontally scroll using touchpad gestures/mouse wheel (as well as by clicking the scroll bars) would greatly improve workflow.

A two-finger swipe (both directions) on the touchpad, or any of Shift/Alt/Ctrl + wheel for mouse control seems a good suggestion.

Since the wheel is mapped to zoom, maybe Shift + wheel could be set to vertical-scrolling, and Ctrl + wheel could be set to side-scrolling.