You must be registered for see images
That's sound genjutsu, Kabuto trapped Edo Itachi and Sasuke in Tayuya's sound genjutsu and they got out with plot.
It cannot be summoned back if it's stabbed. That is the purpose of being sealed. Otherwise Kabuto would've brought back Nagato after Itachi sealed him.
That's all he did indeed. And with that Nagato's vision was rendered to his eyes only. All it took was his weapon mastery.
You're basically saying "all he did was this" and "that" without realizing that you're admitting it only takes that much to defeat the Rinnegan's abilities, and by default the Six Paths. Itachi is a genius of tactics and analysis, after knowing which ability each path uses, it wouldn't take much effort to devise a proper counter against each. And as you said, Amaterasu is enough to deal with the summons.
The people that make any fanbase look bad are the ones who stubbornly stick to a single belief of a character's strength. And take it upon themselves to refer to other readers as "Itachitards" "Narutards" etc. Simply because you disagree with their character choice or argument.
Itachi attacked the summons when Kabuto had Nagato focus on Naruto and Bee, same thing wouldn't happen if they were all focused on Itachi especially if its the Pein's 6 paths who can just dodge it and we saw them fight in perfect unison against Jiraiya. As we seen against Jiraiya, if you surprise attack 1 Pein, if only just 1 Pein sees that Attack then the one being attack can block or evade that attack without looking. Also Itachi wouldn't figure out all of thier jutsus, Jiraiya was busy trying to analyze who Pein was and what he can do and he died plus the only way to see the power of the one that pulls out souls is to get your soul pulled out and DB said when you're grabbed you can't move as seen with Shizune; Naruto was only able to because of KM as it can even break out of shadow possession and Shino's dad bugs can't do anything to it.
Now let's look at Itachi's MS usage, he shown to use 4 MS jutsus against Sasuke before dying plus some little jutsus like basic genjutsu and katon. Itachi use Amaterasu on any Pein or summon and Deva Path can repel that or Pretha path absorbs it. The bird drops exploding eggs while Asura path shoots missiles and with share vision they won't look sight of him plus Deva path can use non Rinnegan jutsus as shown with his raining jutsu that tells him where others are and is how he knew Jiraiya infiltrated Rain village. Also Itachi closes his eye to build chakra before using either Tsukuyomi or Amaterasu which gives time to attack him. Susanoo is roughly the same size as a giant toad, Deva Pein sent 3 giant toads flying miles from him breaking their bones so Susanoo can be sent flying too.
Itachi wouldn't know of the 5 secs interval in Deva Pein ability and nothing stopping Pein from pulling Totsuka blade and Yata Mirror to him and since Itachi would be distracted by the summons its a great way to disarm Susanoo (unless Itachi resorts to Susanoo blades that he used in V3 as an Edo. CT and it's over. Nagato knew a lot about Itachi, he was the leader and Zetsu who record things reported to him and Obito; Obito even called Nagato leader after Akatsuki though "Tobi" died with Deidara so Nagato would know of a Itachi's skills and some jutsus.
