Itachi is NOT a failure.

[USSJ Future Trunks]

Itachi sacrificed the entire Uchiha clan in order to prevent war

that in itself is a fail. the war still started and he sacrificed his parents for nothing and spat on what they died for by torturing sauske to madness.

He also stopped the Edo Tensei

wrong. the alliance did. dont deny they had already taken care of 99% of edos before itachi even got there

But, he was still credited as a guy who protected the shinobi world- if the Konoha found out that the person who canceled the jutsu was the traitor, Uchiha Itachi and learned of all the sacrifices he gave, they might consider him greater than the Hokages

wrong. hes still a murderous psychopath and if they learnt he was the one who pushed sasuke down this path then theyd hate him i bet. and he would have lost without sasukes help vs kabuto. so your basically saying itachi deserves 100% of the credit for things he didnt do alone.
he did more to destroy the world than help it.

But he is a great character and a great man. ^^

hes a brutal evil sociopath who tortures children. hes not a great man at all.

Itachi is a hero

itachi is one of the worst most evil villains in history.
- commited mass genocide
- ordered the attempted murder of 3 jounins
- savagely tortured kakashi and 12 year old sauske into a coma
- cruelly mocked and mindraped 6 year old sasuke and pushed him down the road of hate loneliness and suffering.
- brutally broke sasukes arm and beat him into a coma without any remorse.
- humiliated deidara after recruiting him into akatsuki, strengthening the most dangerous organisation of criminals in the world.
- aided akatsuki in defeating jinchurikis and helped murder them.
- failed to pass any intel about the enemy to his village.
- failed ot even try to neutralise akatsuki members. sasuke and kakuzu did more to bring that organisation down than the man actually trying to stop them.
- almost got team gai killed by opening his fat mouth.
- almost lost the war by thinkig he could take kabuto alone instead of declaring a "kabuto first, tobi later' policy with naruto and bee.
- almost lost the war by relying on a fluke to break himself out of edo.
- made sasuke hate konoah even more and unleashed konohas greatest threat with his blessing of "i dont care if your a genocidal evil criminal, i still love you" bullshit.
- constantly got in narutos way and mindraped him. which led to gaaras death.
- constantly was ignorant of everything around him and failed epicly to watch tobis movements leading to jiraiyas death.

Now, Itachi removing someone like Muu from play was very helpful, as 'numbers don't matter' against such a powerful Kekkei Touta user

.
he cant use dust when half of him is sealed

His contributions to the shinobi world and the village makes him> most Kages; therefore, he's not a failure.

his contributions of unleashing psychopaths and getting people killed?