I think it's quite the opposite. Hardly any of Itachi's techs would be able to hit him, amaterasu can be dodged and so can totsuka blade. Considering the level of Obito's reflexes enhanced also with his sharingan, that shouldn't be much of a problem. His intangibility would let him get inside of susanoo and teleport Itachi.
Even if Itachi knew about Kamui, he doesn't have the means to outmaneuver that we know of. Minato was able to land a hit through FTG, Konan was able to control millions of paper bombs at once. But Itachi only has straightforward techs and melee isn't much of an option, unless he wants to get ported.
The only plausible way to hit Obito is to spam amaterasu until Obito's intangibility runs out, but that's unlikely because itachi would waste all of his chakra since it would be 5 min of non-stop Amaterasu.