Jon,
I am curious what you think is too heavy to throw? I think the advantage of the weighted balls is that the work is very specific and the arm moves slower. How much over 5oz is too much? I have seen several studies showing that weighted balls help with velocity and arm health. Most notably Dr. DeRenne's Power Baseball. He did 8 studies with overload and underload and reported next to no arm injuries with increased performance. I am sure ASMI also has a study that shows performance enhancedment but no indication of increased risk to the thrower. I know their original study was in 99 and had no injuries to report. Do you have any actual data of someone under a well thought out program that was injured at a higher rate than anyone throwing regulation balls?
Chris, the body doesn't know the difference between a long throw and a short one. It only knows the amount of force required to meet the goal of the person throwing. You can throw max out into a net ten feet away or you can lob a ball across the diamond.