Granted his hype is overwhelming and most people may end up being dissapointed due to Kishi refusing to showcase any of his skills, the fact that Orochimaru had to wait until Hiruzen was 69 and use psychological warfare by summoning nerfed versions of his former teacher who themselves are monsters should be considered a testament to how strong he was in his prime. But instead, most people tend to underrate him. You're merely creating a battle of everything Orochimaru has shown vs what Hiruzen has shown. Yes, Orochimaru was toying with him, but he had to be prepared in order to do it. No one looks for the silver lining anymore.
Karyu Endan (which turned white-hot, mind you) and Doryuheki were B-Rank, same thing as a majority of Kakashi's techniques. But then again, anything not S-Ranked are considered "weak" by members, right? And Enma is considered a strong summon. Most people underrate him just because he's not the size of Gamabunta.
But alas, this is Naruto, where if it's not at least the size of Gamabunta or fits in your eye socket, you suck.