Anyway, here's what I think:
Close-range
Kakashi's skilled, but Itachi has the edge in speed and weapons. His hand-speed makes his shuriken and clones much more difficult to deal with even without sightblockers (which Kakashi uses,) not to mention Itachi's taijutsu seems more refined. Moreover, genjutsu―while Kakashi can break through it―can still buy Itachi the fraction of a second he needs to cut Kakashi. Basically, if Kakashi is going to win, then he needs to pull back to mid-range and make this a battle of ninjutsu. That's exactly what Hebi Sasuke chose to do, and Hebi Sasuke was overall much deadlier in close range than Kakashi.
Mid-range
Now Itachi's in a bit more trouble. Kakashi is more diverse in terms of ninjutsu, with a better elemental distribution, and can overpower Itachi this way. On the other hand, Itachi has very hyped seals, which means his ninjutsu is likely to be executed faster, but more to the point: Kakashi can't see what he's doing with his Sharingan, but Itachi can preusmably read Kakashi's seals (if there's no sight-blocker) because Kakashi's seal-speed was never hyped like Itachi's was.
Moreover, now that Itachi has 100% of his chakra and is focused purely on Kakashi, then he's going to use clones too―he uses them in literally every other battle where he had normal chakra. Now, both have game-ending bunshin if they land. The Raiton bunshin will paralyze Itachi and make him vulnerable, and the exploding bunshin will maim Kakashi.
However, the bigger point here is the Karasu Bunshin. Not because of its power, but because of its efficiency. Other types of bunshin take 50% of the user's chakra, but Karasu Bunshin were stated to be very efficient. Itachi used them multiple times on the same day he used Mangekyō jutsu. This means Itachi will actually be able to use clones more often in battle, and thus in a ninjutsu battle, he'll have double the firepower for half the price.
But even more prominent is Itachi's shunshin jutsu. It's been shown off multiple times, and it's very refined, probably only second to Minato, A, and Naruto. With his shunshin and reflexes, Itachi can probably dodge Kakashi's ninjutsu rather than be forced to counter them. Are the pieces adding up? Itachi has the more efficient style. Even when sick, it would likely be Kakashi who tired first because Itachi's fundamental skills are so advanced.
Laslty, Izanami. Essentially, with being able to use multiple Karasu Bunshin, Itachi only needs to have Kakashi kill two in the same way. We know Kakashi can sustain Raikiri and has even killed multiple clones that way. That would be the perfect time to capture him in the Izanami's loop.
Hype
It's pretty undeniable, I think, that the author holds Itachi in higher regard. So in a sense, this match could just be argued from a "Tobirama vs Kisame" perspective. And by that I mean that, in terms of feats and logic, Kisame stomps, but that if a battle actually occured then you know Tobirama would be the victor because of the raw portrayal. In this case though, I think Itachi actually has the feats, etc. to beat Kakashi though.