I think so. Edo Tensei, Curse Mark, and the soul transfer jutsu are top notch. He's around the top 10. Plus, we have no idea what else he knows now, especially since he created Mitsuki.
He will eventually be number one.... considering he will be the only Ninja who lives past the peaceful ages. Everyone else will become weak, and their kids will be weak as well. They will never know the horrors of Naruto's generation and the ages prior.
With Edo-Tensei, curse mark, soul rebirth and Triple Rashoumon that puts him way up there. Honestly if you take away KKG based jutsu/abilities i would argue to say he is or potentially is #1
Sad thing is people forget Orochimaru couldn't use seal based jutsu the entire series until the end due to Hiruzen's Troll
Based on Kabuto's arsenal it only works if he is in a cave. In open terrain Kabuto's effectiveness drops tremendously except for his immunity to normal genjutsu
Orochimaru went through the entire series without seal based jutsu AND the one fight he was in with use of his hands he toyed around lazily. Based on Feats Orochimaru by design should be superior to Kabuto in every way EXCEPT analytics