I was 12 in 69 so I remember more about it than some of you. They originally proposed removing the talus, but when they dewatered they realized that the talus pile was holding up the face of the American falls. So they did nothing to it. They installed a bunch of sensors to allow them to detect any rock movements and be able to protect the tourists.
They are dewatering it this time to rebuild the bridges to Goat Island. Last time I was there in 2013, Luna Island was closed for renovation.