Well, in all fairness, all it took for Hal Jordan to have a turnaround from evil galactic scumbag to superhero was a six issue mini-series.
I just feel really bad for all the Iron Man fans out there; can you imagine having your favorite character turn into a bad guy? It can't be good for sales!
Here's my thinking; Marvel wasn't intending for people to have such a negative reaction to Iron Man. They wanted to create a morally ambiguous character who, while he believed in doing good things, nevertheless had a questionable way of going about achieving them.
Unfortunately, in comics, especially Superhero comics, that Alan Moore slant to superheroes can only go so far before people start hating characters.
Can we all say that we really liked what happened to a majority of the characters at the end of Watchmen? (Don't spoil it for those who haven't read it

).
So, in trying to create a hero for the 21st century who would do whatever it takes to save the world, Marvel instead created one of the biggest evil scumbags in comic book history. Here's to hoping Hulk's thumping of him knocked some sense into his tin plated head.
(Go She-Hulk!)