One villain that was always capable of keeping up with Stark was The Ghost. His powers of intangibility pose a threat no repulser blast can stop. Updating his other rogues would be easier than one think -
I would also like a story that would reintroduce The Ghost as a Iron Man villain. Ghost is hunting down supposed members of a global conspiracy. Problem is: Ghost has paranoid schizophrenia, in his mind he creates imaginative enemies.
So are group of buisnessmen ask Stark for assistance because he has the most experience dealing with Ghost.