One thing that's more obvious from the pics is that Kakashi's eyes definitely look less stressed compared to Itachi's. Itachi's looks like his eye's just gonna crack. But that might just be from the degree of use each person's had. Kakashi's new, or 2yrs max, whereas Itachi's had his for 10+ years. I like the genjutsu/ninjutsu explanation. Just have to wait for an explanation on Itachi's black flame technique now. You need Mangekyo Sharingan for that jutsu, and it's certainly now genjutsu.