I agree, Norman *is* good at what he does - screwing with Peter's head. Because he knows his secret identity.
But can you really put him in the same class as the Avengers? Spider-man was uniquely vulnerable because he was unwilling to give up his secret identity until very recently (and then retconned away). Norman was laced into Peter's history through the death of Gwen Stacy and his son's friendship with Peter. Norman was effective because he was a very personal foe.
Now, if it's the Kingpin, or Baron Strucker, or Zemo, those are people that I can find some root for the MU to be wary about.
Again, Norman's rise is, as I see it, due to the military-industrial complex that laces American politics. As we've seen, people who have come from a corporate setting don't necessarily (i.e. rarely) translate well to a government setting - so my only glimmer of joy in having Norman Osborn be at the head of National Security is so he can be, hopefully, erased once and for all.
Because, again, seriously. Norman Osborn. Claim to fame? Killing Spider-man's girlfriend. After that, resurrecting, and playing mind games with Spider-man ever since. How's that compare to, oh, the Red Skull. Ellis made him work because he was clearly insane and fixated with Spider-man still.