IMO, the solution is to use the ATP style racquet takeback, rather than the WTA style takeback. The keypoints in the ATP takeback are keeping the racquet head and the hand in front of the shoulderline, and keeping elbow high and far away from the body. Then you just relax the arm and wrist, immediately rotate the hips explosively which'll extend the wrist at last second, and the lagging racquet will then naturally swing through without any conscious effort.
The WTA takeback is longer, and the stroke is more dependant of your own conscious FORCED push through the contact zone. It's very hard to moderate pace, as all the small changes in your effort will strongly affect how the ball leaves the racquet. With the ATP style it's easier to moderate the effort as the racquet will in any case swing through passively with its' own mass rather than with you actively hitting the ball. The stroke is not so sensitive to small changes.
Do you hit ATP or WTA style?
http://www.youtube.com/watch?v=RMqQ2ys71bw