this is garbage! Edo Tensei is a summoning technique and is therefore part of Kabuto's strength. And Kabuto didnt just learn the technique, he improved it using his ninjutsu proficiency and intelligence. Just like he used his scientific and Medical knowledge to replicate Jugo, Suigetsu, and Karin's abilities, infact, he didnt just replicate them, he modified those abilities to suit his needs. The genetic cloning and enhancement of Manda also proves just how capable Kabuto is. This man has achieved a lot and to take edo tensei to the level he has taken is out of this world. This guy even improved Zetsu in just one day and was able to create 100 000 clones of him, captured Yamato and used a truth serum (which he created) to interogate himwithout killing him. Mastered dragon sage mode and so many other achievements in such a short time, these are things that Oro couldnt achieve, sure the ideas (some of them) were Oro's, but Oro never managed to complete them and Kabuto did it in the space of a few months. Stop trying to underate Kabuto, he deserves all the respect he has earned, he worked hard for it and sacrificed a lot to get there.
If you gonna complain about Kabuto using a summoning technique that he improved and modified, then complain about Jiraiya's summonspamming in battle, complain about all the summoners in the series as well. and take away their summoning contracts. Here's a copy from Narutopedia....
Summoning: Impure World Resurrection
As a further testament to his corpse theme, Kabuto can perform the Summoning: Impure World Resurrection technique — which only Orochimaru and Tobirama Senju could before. Kabuto states that his usage of the technique surpasses that of the two other users, and he supports that by resurrecting five deceased Akatsuki members at once. He also states that he can resurrect many other powerful ninja under his control, including Madara Uchiha. He applied a seal on the corpses that doesn't completely rob them of their free will, but still controls their body movement against their will — a seal different from the one Orochimaru used. Kabuto showed his great prowess in this particular technique by summoning a large group of famous and powerful shinobi, including deceased jinchūriki, Kage, and many others. He is even able to remotely monitor the bodies as well as re-write the commands given to the resurrected people, allowing him to rob them of their free will whenever he wants.
Like his mentor Orochimaru, Kabuto has shown himself as an extensive researcher, performing multiple experiments to increase or neutralise an individual's abilities, as shown by his creation of Manda II, his intricate knowledge of the Wood Release, his mastery of the Summoning: Impure World Resurrection, the empowering of the Zetsu army, his enhancement of Madara's "golden age" body and the enhancements done to his own body by studying and reverse engineering the abilities of team Taka.