It would be interesting to see photos from previous decades to compare to today. I've probably run it 30 times or so starting in the early '90s and it does seem like it has changed some, but it is tough to put my finger on it. I'm never sure if it is just different water levels that change the eddies or rocks moving around.
On a side note, I just finished reading A River to Run, Glen Wooldridge's biography. He was still alive in the early '80s when the book was published, and he was lamenting not finishing the job (blasting) to make it safer than it is. I hadn't realized until reading that book that the channel he tried to clear with dynamite ran down the left side, but rocks rolled back into it from the canyon wall forcing the move back to center that exists today. It is certainly not intuitive at all, and apparently is kind of an accident/compromise.
Don't get me wrong, I am not advocating blasting anything, but Blossom in it's pre-dynamite configuration was not runnable at all except at very high flows.
Show me your OOOOOO face