I agree. Amaterasu is isanely powerful. I wonder what ever became of Jiraya's analysis of Amaterasu. Remember, he sealed some away on a scroll?
Anyway, it leaves me wondering "Why?" Why is Sauske's sight already diminishing after only two uses of the Magekenyo Sharingan? I know that perpetuates the users blindness, but I thought it would be a bit more gradual than wha we are seeing. Itachi, presumably, kept his eyesight for YEARS after activating Magekenyo Sharingan, and we KNOW he used it more than twice! Once on Sauske as a child, once on Kakashi, once to escape Jiraya's Mountain Frog's Stomach Jutsu, and who knows how many other times he may have used it when we weren't looking.
That being said, I think either Madara or Itachi may have accelerated his blindess. Perhaps each for their own reasons, but with one goal in mind: To get Sauske to take Itachi's eyes.
I have a hard time believing that Madara would just cast them aside and wouldn't preserve them.
That is, of course, if the eyes Sauske is using are not already Itachi's. *evil grin* No one knows what happened to Sauske while he was sleeping after his battle with Itachi.