I can agree to a limited extent with your post Mega regarding predation, and I certainly cannot argue from an infectious disease perspective. From the 50,000ft up POV, having seen the glory years of turkey hunting in our county I simply cannot agree with the overhunting aspect. The pressure the turkey population received was probably as much or more than anywhere else in the country, and the turkey population sustained if not grew. And then in a matter of a couple of years the population nose dived.
I do think that from 1995-2005 were the absolute peak years in turkey numbers and that there are natural cycles in population. However this doesn't "feel" right. There are many areas of the county that are void of turkeys now that carried hundreds of birds per square mile. I believe that it would be hard to prove that natural predation could have that impact.