0_Jordinio_0
A little or perhaps too much of a stretch for Hiruzen to be able to use the jutsus once he sees it, though if it were that easy to do that Kakashi wouldn't be a thing and discretion over jutsus would be useless.
I said that but I actually liked it, the original series underestimated the character a lot, his title is God of shinobi but he didn't show anything great, far below Hashirama and Tobirama.
0_Jordinio_0:Not really actually. As a 5 year old child, Itachi was capable of copying jutsu on the spot even without the Sharingan, this was before he ever unlocked it. It's well within the capabilities of Sarutobi.