wow that is an amazing fish I just love the way browns get all crazy looking. Just look at the size of the head and neck compared to the rest of his body it's almost half the fish. That is a spectacular fish congrats.
Sometimes I move fish by accident and place them where they come to hand and not always in the same spot they came out of. Not sure what good or bad I do by this but I try my best to release fish with the least amount of stress less the catching part and chapped lips. Maybe your catch had a good food supply drifting down to him in the slot he was in? Moving him to faster/more water could stress him or maybe he becomes the big fish in the pool who knows but again what an awesome fish!
Andy