The copying I don't blame too much for not being in focus, given how we started getting proper explanations on how some of the Jutsu worked. It wouldn't make sense for someone like Sasuke to be copying hundreds of Jutsu given most used in combat are either hidden family Jutsu(like the Nara clan's Shadow stuff), or elemental jutsu. In Part II we learn about how the Chakra natures work, so it'd make sense for them not to be used on a major scale when Sasuke was stated to have Fire and Lightning natures.
Of course, Kishi started getting loose with his rules on this stuff particularly toward the end. Despite them stating pretty clearly "People have one predominant nature and a second, some very skilled people can use multiple" , we got one of the last databooks listing almost every character with three natures. And now in Boruto he's using lightning, wind, and water style without even being officially a Genin. Even in the war, we saw the entire alliance using Earth chakra to create a wall to block the 10 Tails attack, which really shouldn't make sense since we know some people just shouldn't be able to do that. Despite it being said to be an "easy Jutsu everyone can do". Kishimoto is honestly fantastic at world building. His problem is that he makes these pretty detailed systems and then just breaks the rules of them when he wants to tell an interesting story.
Only cool part that I liked about that aspect of it was solidifying the statement of the Third Hokage knowing "every Jutsu in the Leaf". Might seem like a hyperbole, but then in the war he was busting out every element and then some. We're here talking about Sharingan, meanwhile Hiruzen learned everything without magic ninja eyes.
On a last note, it is disappointing that Kakashi was specifically titled the "copycat ninja" yet we only saw him use a few Jutsu outside of his kamui and Chidori variants. He did some cool stuff like the Lightning Clone, but again that kind of is just the 4th or 5th variation of the Clone Jutsu we had seen at that point. I would have loved to see him retain some those skills without his Sharingan, but from what I hear of the novels, Kakashi claims to be useless without being able to do his Chidori properly after the war until he makes some generic Lightning Jutsu.