Originally Posted by Night Raven
Count Nefaria did appear in Iron Man, as he was the father of Madame Masque, and Masque was a constant storyline in the comic.
Ghost - well it's arguable that Whiplash in the comics couldn't carry a movie on his own either. The way he would be written, he would be made to be a compelling villain.
Grey Gargoyle did run in with Iron Man a few times, and was even in the 90s Iron Man toy line, so he is maybe more associated with Shellhead than Thor.
Madame Masque is nothing like Hammer - she's more like Black Widow combined with Viper (the head of Hydra). She was always seeking revenge for a) the apparent death of her father (he wasn't actually dead) b) being spurrned by Iron Man as a former lover b) because she had a personal grudge against Bethany Cabe, Tony's later girlfriend who was a physical match for her.
Spymaster - see Ghost.
And again, I highly doubt Favreau would've wanted to use a Superman in his film. As far as future films sure, but then the question is, do they make him a Superman or just a regular guy. If he is a regular guy, who's going to be the physical threat? are they going to bring in the Dreadnoughts or is IM just going to be lopsidedly beating up on mobsters? Ok lets do the Dreadnought, oh but wait, "why is Iron Man fighting 10 foot tall robots again?"
Ghost would be fine in future films as long as he's just the underling to a bigger bad like Mandarin, Crimson Dynamo or Titanium Man.
Wah??? GG only appeared twice in the Iron Man comics, waaay back in issue #235 & #236 (fyi, they're at 500). But even if he is considered an IM villain, he's at the bottom of the barrel.
I know that about MM, but what I was trying to say is she wouldn't be a physical threat to IM, that's what her Dreadnought robots are for, which goes back to the old, "why is Iron Man fighting 10 foot tall robots again?".
Spymaster, like you said, see Ghost.
Don't get me wrong, I'd love to see Madame Masque, Ghost, Spymaster etc. make it into these films because of the psychological threat they bring in but as far as the physical threat, like I said before, it comes with the territory.