I still have to see a comporable or lower power person than me that uses edo hashirama so i can't say much about it in terms of how good he is in that situation, but i can tell you that itachi susano'o strictly requires that you own an overstacked move 1. I've seen a lot of itachi used by people with comparable or lower power than me and he is not a serious issue to deal with, unless he is paired with shisui and also madara founder, mostly with fire or wind main (but also that lineup is actually beatable on par power).

What i feel about edo hashi is that he is meant to be the best possible support for water main, just not the neurotoxin version, and for wind main, just not in the common versions she is right now used.

A lineup like: edo hashi, water main, kabuto snake cloak, kisame samehama/edo sasori/tsunade sannin war full sb with 1st mystery mutation, for example, is extremely hard to beat, but is slow in making you win the battle. In the sense, you actually kill your enemy in round 5+ with a 15k/20k shark bomb and a 5k 4th chase (that scales up fast with nature energy gathering boost) while you wholly shut down or endure them in the meanwhile, but is still round 5+...