Spidey was pretty much out when Venom tied him down and giant Sandman was slamming him. Only Harry's intervention saved him. Same with when Venom tied him down the second time and Harry took the hit.
Ahh but he wasn't actually out, he was just lying there helpless, taking a beating but he was still conscious.
And by comparison Ock only kkcoked Spidey out because he was already out on his feet from stopping the train. And the Golbin used kocked out gas. he didn't beat Spidey to unconsciousness.
But that says more good things about Ock and Norman. Those 2 villains respectively were the only threat against spidey but still managed to get spidey into a more vulnerable position...by themselves respectively.
Norman used knock out gas, even though the spider-sense should have warned him but whatever, he still got 1 up on spidey. Now, during that time of unconsciouness, spidey was at Norman's complete mercy, Norman could have killed spidey in any way he desired. Part of the KO gas had a chemical that paralysed spidey so, even when spidey came too, he was still helpless.
As for Ock, I salute his villainy for what he did, he destroyed the controls and took off, leaving spidey to either struggle and endure pain and exhastion from stopping the train should he succeed or he'd die trying, either way, Ock left spidey in a weak position, that was just good strategy on ock's part. He didn't have to knock him out, had Harry not wanted spidey alive, Ock, going by what we saw in sm2 could have easily killed spider-man.
As for the bad 3 in sm3.....there were 3 of them spidey was going up against in that movie and each as individuals showed the same amount of potential and in some cases more to really dish out the pain and potentialy kill spidey more so than Norman and Ock but Harry turned out to be a mere excercise, he posed the least physical threat in all 3 movies, sandman again, probably the villain in all 3 movies to have the highest potential to kill spidey posed little threat but one could argue that was due to the way his character was written, sandman isn't a murderer and then there's venom. He just didn't bring it as he should have but again, one could argue he had little time to work with but I can think of at least 4 chances he could have capitalised on in killing spider-man.
So ultimately, even though I think sm3 is the best comic book movie ever made, its flawed and there are things in sm1 and 2 that came off better regarding certain aspects. Norman and Ock respectively as individual villainous entities posed more of a threat than Harry, Marko and venom combined in 1 film.