lol? Orochimaru is only Top 10 if ET is factored in. With or without arms I can name more than 10 people who beat him.
Obito
Hashirama
Madara
Naruto
Nagato
Kabuto
Sasuke
Minato
Itachi
Mu
3rd Raikage
Tobirama
Onoki
Jiraiya
Trollkage
Sasori
I don't understand your reasoning.
1. With arms he has Edo Tensei, giving him access to the power of multiple characters that are in your list all at once.
How does someone like Naruto beat the combined power of Orochimaru, Hashirama, Tobirama, and Minato? Or how about the combined might of Orochimaru, Trollkage, Muu, and 3rd Raikage? Orochimaru also had access to Madara.
2. Barring Edo Tensei as a factor, you're almost entirely basing your view of Orochimaru's power based on his armless feats. If you'd like, you could name 5 jutsus that we haven't seen him use without arms.