Another trick is to slow the replay down to 1/2 or 1/4 speed (press F2 to slow down, F3 to speed up), record at the slower speed them speed it back up in your video editing software.
along with the 1/2 or lower speed replay trick, i believe setting the "movement speed" also affects how fast the mouse can pan the camera. try playing with that and seeing if it changes anything.
(movement speed, the slider that changes how fast the camera moves with the arrow keys)