Top-Tiers: Rikudou sannin, Hashirama, Madara, Pain, Sarutobi (is not expecting everyone to agree )
When Deidara met Kakashi, Kakashi held his own! And later on even half way defeated Deidara. Deidara later on warned Hidan and Kakuzu about meeting Kakashi.
Deidara to Kakuzu and Hidan; "If your going to Konoha, Ive got one bit of advise. be careful."
When Itachi met Kakashi, Kakashi was holding his own and impressing Itachi...
Almost too much! Even if Itachi didn't intent to fight for real, Kakashi had no clue, yet he was not frightened. And was actually planning ahead like how a ninja is supposed to do being aware of who Itachi is, you now, "The man who whipped out the legendary clan".. Yet still was forced to flee several times.
Itachi; "As expected of Konoha's Kakashi"
When Pain met Kakashi, he immediately acknowledged Kakashi's strength in his God form. And Kakashi being aware of how powerful Pain is, 'killing one of the legendary sannins', he still was not intimidated. He confidently stood up and actually suggested to take him head on, sending Iruka away, almost reminded me of Minato. The way he was the first one who took actions against such powerful ninja.
God Pain; "I'm honored to meet you Kakashi, the copy ninja"
And don't let me start on Kakuzu and Hidan. Because Kakashi's confidence was overwhelming at start, the way he crushed Kakuzu's heart.
All this, whether they wanted\want to fight or not, he mostly had little clue, all he was thinking is to deal with the opponent before they do any more damages.
I'm not talking about power lvl here. I'm talking about GUTS! How to have the guts to actually intent to dispose of such powerful enemies. And do what a Shinobi is suppose to do! Stand up and fight in before his opponent and never give up. Kakashi has been known to have copied over 1000 jutsus. Kakashi is more Hokage material then Tsunade actually is.
That same man met Orochimaru. And what did he do?
The son of Konohas white Fang, found himself helpless.
He literally froze, overwhelmed by the killing intent of Orochimaru.
Where did the brave shinobi go? He doubted his way of a ninja.
Orochimaru didn't even touch him nor did he threaten him, all he did was stand there.
Kakashi met Gaara, a guy who oozes of killing intent, lives to kill (At that moment). How did Kakashi react to his killing intent?
Not even amused.. >_>
We can ask ourselves...How much more desire to kill and hate does it take to surpass Gaara's killing intent? What kind of power do you think takes a genius like Kakashi to be so frightened?
This is not to degrade Kakashi's strength, it only is to show the difference of effects people he met had on him, because on forums Orochimaru is severely underestimated. And this strongly proves why Orochimaru is top tier and should be acknowledged.
Kill 2 of the greatest Hokages, create you're own country, create immortality, bring back people from the dead, refuse to die before accomplishing you're goal, halfway destroy the most powerful village in Narutoverse , brake every rule of humanity, the list goes on...
I guess you'll just be hated even as a villain when it's you're job to act all villainesque and hurt people for the lulz. Kishi needs to give Orochimaru some fancy eye's, so then he'll have a bunch of mindless fanboys to label him as god...>_>
The brilliance of Kishimoto is the varied types of villains he presents.
He made Orochimaru come off at his best, then showed the reality that even such powerful entity's has to struggle their way, putting him aside for a while so he can focus on letting other issues came to conclusion and rest in piece, and later bring back Orochimaru and complete his purpose for the manga. Then he'll be at his best as a villain. These over hyped 'yet not so powerful' villains who lack everything that is needed from a villain will vanish soon, it's their fate. From the beginning, Orochimaru is not bound by fate.
He was the one who put things to start:
And he will be the one ending things. He will die in a way worthy of his being.