Okay, so, reporting test results.
There is a definite improvement with the provided fixed version. However, it is still not the same as it was pre-breaking or when using the mouse.
Before, the drag-action would make the cursor move with a speed dependent on the touch input relative to the center of the screen. (i.e. as if it were a virtual joystick centered on the screen)
Now, the drag-action makes the cursor move with a speed dependent on the touch input relative to the original point of the touch input. (i.e. a virtual joystick centered on the initial touch point)
When using the mouse (or touch-drag in older versions), the cursor stays glued to the position of the mouse pointer, only moving when the mouse is moved.
In both touch-input situations, the cursor will rapidly move towards the edge of the screen, but the scrolling action will continue as if the cursor was still moving away. Turning off edge-scroll does nothing to prevent this behavior.
System used is Windows 8 x64, on a Samsung ATIV Smart PC Pro (ATIV Tab 7), running latest Wacom Dual Touch (ISD 720.4) drivers.