Here I'll write an alternative timeline in which Orochimaru imprisons Sasuke for three years instead of training him.
Knowing about Sasuke's potential, Orochimaru would imprison him instead of training him, preventing him of becoming a threat.
After 3 years, Orochimaru takes over Sasuke's body.
With a new and strong body, Orochimaru goes after the reaper's mask to recover his arms, using Sharingan to make someone wear the mask for him.
Pain tells Akatsuki about Sasuke's death. Itachi and Kisame decide to chase Orochimaru to kill him and capture Naruto, who'd probably chase him too.
Tsunade and Jiraiya tell Naruto and Sakura about Sasuke's death. Jiraiya, Kakashi, Naruto, Sai, Sakura and Yamato form team up with Team 8 on a mission to find and neutralise Orochimaru.
Orochimaru decides to get stronger, so he could defeat Itachi and take his MS. In order to get stronger, Orochimaru starts honeying the Sage Mode on Sasuke's body. He also infuses Hashirama Cells in his body.
Itachi and Kisame find Orochimaru first than Naruto's team. However, Itachi refuses Kisame's help and decides to fight Orochimaru on his own in order to avenge his younger brother.
Itachi is defeated and his MS are taken by Orochimaru (who doesn't awaken the EMS, since he didn't have a MS of his own). Kisame forces Orochimaru to flee and notices Naruto's approach, starting to chase his team.
Kisame fights Naruto's team and is overpowered by Jiraiya, Kakashi and Naruto, but manages to flee before dying.
Orochimaru, still recovering from the fight against Itachi and with Kabuto's help, summons the 4 Edo Hokage, controlling them with amulets to prevent them from breaking his control. He sends them to fight Naruto's team.
The 4 Edo Hokage defeat Naruto's team. Jiraiya sacrifices himself to let Naruto and the others get back to Konoha.
At this point, Orochimaru has:
Itachi's Mangekyō Sharingan (Amaterasu + Tsukuyomi + Susanoo).
Perfect Sage Mode.
Hashirama's Cells (which restores his vision and eventually awakens the Rinnegan).
4 Edo Hokage (fully controlled).
Resuming the alternative timeline, Orochimaru would train to improve his physical prowess with Sasuke's body. Meanwhile, Kakashi, Naruto, Sakura and Tsunade continue to mourn Sasuke's and Jiraiya's death. Naruto blames himself for letting both die and not fulfilling his promise to Sakura, who asks him to forget about it and keep on his way to be Hokage. However, Naruto doesn't want to be Hokage anymore since he couldn't save neither his best friend nor his master. He's actually getting consumed by Kurama's hatred at this point.
Once recovered from his battle against Itachi, Orochimaru decides to resume his plan of crushing Konoha. Unlike his first plan, which consisted on disguising himself as the Fourth Kazekage, this second one consists on simply destroying everything with his snakes and the 4 Edo Hokage.
Meanwhile, as neither Sasuke or Taka is allied with Akatsuki, Tobi and Deidara go after Killer B to capture the Hachibi, which they succeed.
Orochimaru attacks Konoha with giant snakes, immediately causing everyone to know what's happening. Naruto, furious and fuelled by Kurama's hatred, goes to fight Orochimaru along with Kakashi, Yamato, Sai, Team 8 and Team 10, as Team Guy is away on a mission.
The Edo Hokage easily overpower the Konoha-nin, killing all of them except Naruto. Orochimaru heads to the Hokage Tower and fights Tsunade, who he easily defeats even after she uses the Byakugo Seal. Orochimaru becomes the self-proclaimed Sixth Hokage, also killing the elders and only sparing Danzo, who manages to convince him that he'd be useful as his right-hand man.
Now, as Hokage, Orochimaru starts a dictatorial regime in Konoha, imprisoning Naruto and killing Team Guy when they get back, only sparing Neji, who he imprisons to study his eyes. He'd eventually clash with Akatsuki as they'd go after Naruto, but he would easily defeat them all, even if they attacked Konoha with all the remaining members (Tobi, Pain, Konan, Deidara, Kisame and Zetsu). He'd also take Tobi's and Kakashi's MS to awaken the EMS, as well as Pain's Rinnegan.
Finally, Orochimaru would start raiding and destroying the other villages to have them under his control and be able to study every kekkei genkai in the world. He'd kill the Daimyo and rule the Five Great Shinobi Nations on his own.
Eventually, Orochimaru would learn that becoming the Ten Tails jinchuuriki would make him immortal, so he does it by summoning the Demonic Statue of the Outer Path and extracting Kurama from Naruto to get all the 9 Tailed Beasts' chakra for the Juubi and become its Jinchuuriki.
Orochimaru wouldn't want to proceed with the Eye of the Moon plan, and so Kaguya would never ressurrect. Even Black Zetsu wouldn't stop him since he couldn't manipulate and deceive him. At somepoint, Orochimaru would fight Momoshiki and Kinshiki and would find no problem on beating them down by himself.
He would finally achieve all his goals:
Becoming immortal.
Learning every technique in the world.
Having his revenge against Konoha.
Controlling the world.