I just saw and read through all of the many prior posts on this topic with interest.
I am certainly not a proponent of dams, but I do understand why a number of them have been built, and both their historical and present importance in a number of these instances.
As a youngster, I was born and raised in Warren, PA at the confluence of the Allegheny and Connewango rivers. I was there and experienced devastating floods in the mid-1950's. Although my family moved away in 1960, I married and returned to live in Warren briefly in the mid-1960's, worked for the US Forest Service and helped survey and build a number of the recreational facilities and roads around the Kinzua Reservoir.
I have long since moved from that area, and now reside in SE PA during the winter, and SW MT during the summer. I am now what some of you would call an Oldtimer, but during that lifetime I have fished most of the rivers extensively that have been mentioned in this thread, and while I am now mostly a devoted trout fisherman, I have also fished for many other species with a number of other means, so I by no means would label myself as a purist only fly fisherman of trout.
However, having now seen and experienced a number of the issues and arguments' sides in this regard, and from different geographic, economic, social, etc. perspectives, I would say from my perspective that once we have justified putting these dams in place, and there is no compelling reason to remove them, then we should take those steps that are practical to receive the most overall benefits from them. If that overall benefit is to turn them into a better managed cold water fishery, then I believe it should be done.
Now, I tell you, I'm leaving PA behind until next Fall, and will soon (I hope) be fishing below one of the several dams on the Missouri...or I might just have to fish below or between one of the several dams on the Madison. Or maybe, just maybe...
John