As far as I remember, Shisui was actually the one doing the stomping. Danzo only got him after he used Izanagi, which caught Shisui off guard because obviously, the guy isn't an Uchiha.
Although it's true that it's mostly hype, he was said to be the best Uchiha of his time at a time that Itachi was around and he also used to defeat Itachi all the time in training, so it should mean something at least. If anything, they should know all of each other's tricks like Izanagi, complex shuriken tactics, leaving behind clones, dispersing into crows etc. And Shisui's afterimages can actually inflict legitimate damage, instead of being normal mirages.
Shisui was also said to be the best at genjutsu (I think?). This part is hard, because Itachi since gained the Mangekyō which means much better genjutsu and of course, the infamous Tsukuyomi. But Shisui also has the Mangekyō and Kotoamatsukami is portrayed to be superior, but Itachi has knowledge of it. I dunno how this part would go.
I go for inconclusive, because I think it's hard to tell. If Shisui was resurrected, he'd probably have fought Itachi, and we'd know or at least, have a good idea about how this fight would go.