Sasuke has more chakra than Itachi, and can control amaterasu a lot better than Itachi.
Itachi has a vastly better Tsukyomi than Sasuke
Susanoo I am ASSUMING does not contain totsuka sword or yatas mirror but are LITERALLY what zetsu said-Legendary items, and were Itachis, and have stayed as Itachis (unless getting his eyes for EMS transfers these powers) then Itachis susanoo is much more powerful.
Itachi still reigns supreme even over sasuke because of those legendary items.
And even if sasuke did get them, what's better, amaterasu or tsukyomi?
Tsukyomi requires the user to look into your eye so i guess amaterasu, but physical attacks sometimes aren't always the way.
Either way Sasuke & Kisame would own Naruto & Kakashi in no time
Sasuke could kill Kakashi in no time, Kakashi blatantly cant make 3-4 kamuis due to chakra levels, sasuke can make 5 susanoo arrows, bam, kamui, bam, kamui, bam, kaumui, bam, kamui, bam Kakashis dead.
Kisame can suck out 2/3 of Kyuubis power, as samehada can eat 6tails worth of chakra in any one time. Naruto pwned
Ugh, here we go..."sage mode"