The important thing to note here is that Yata will reflect Mokujin's punches while Itachi goes offensive with Totsuka, meaning mokujin can't catch totsuka in its hands like it did with PS slash (PS has faster striking speed than V4 Susanoo but at the same time SM mokujin >> base mokujin which is simultaneously attacking and cannot catch the totsuka blade.) Mokujin doesnt need to go on offensive, but with only manga intel Hashirama will no doubt try.
That happens only one time. Unless he can take out Mokujin in that one exchange, this strategy won't work. Let's say he does take out Mokujin like this. Hashirama himself is still alive, and that doesn't change the fact that he still can't put him down.
-Hobi tanks attacks stronger than what Itachi can produce.
-Hotei's size rivals that of Full Kurama, which dwarfs Itachi's Susanoo and it can catch a superior Susanoo's blade.
Hashirama would still parry him, and still outlast him. Hell, he could even make another Mokujin after the first one is sealed. Itachi can't win here.
Then theres the fact that totsuka doesnt just pierce, it seals. Sure mokujin will take a long time to seal but Totsuka can do the job, seeing how it sealed Edo Nagato in seconds. V4 Susanoo has four arms which can manifest other Susanoo blades and continually land hits on mokujin (which only has two arms to defend itself). Tbh, I don't see base mokujin fending off and parrying an enhanced Susanoo's attacks forever, especially with the Totsuka blade...it would eventually get sliced up before Itachi runs out of chakra. Once mokujin comes down, Hashi is toast.
Susanoo can't manifest other blades. Lol. Never shown in the Manga at all. PS has two Katanas. V4 Susanoo has two blades, Madara's anyway. Itachi's only has Totsuka while Sasuke's has a bow. The only V4 Susanoo that can use multiple blades is Madara's let alone forming extras. Base Mokujin's physical strength rivals Full Kurama's as per the Databook. Itachi's Susanoo would only rival Half Kurama's in strength in Scenario 1, and it'd be near Madara's level in Scenario 2, but in Scenario 2 Hashirama has Sage Mode, so that doesn't even help Itachi win. If it weren't for Yata Mirror, Mokujin would manhandle Itachi's Susanoo.
Unless enhanced Susanoo surpasses Sasuke's PS by far in the physical strength department in S1, he loses. It doesn't, and that's a fact given he is literally the same as Sasuke, but without a Senjutsu boost and plus Yata Mirror, so there is no way he wins or cuts up Mokujin. Same happens in S2. Totsuka Blade's presence doesn't matter if he can't land a hit. Madara couldn't land a direct hit. No reason to believe Itachi can.
Mokujin's defeat doesn't signal Hashirama's defeat. He still has Hotei to parry PS's attacks until he can make another one.
