Me too. I think TH is a great actor in most things he is in. He brings a certain passion and intensity. But I think that is part of the problem as he is like that on set as well.
I just decided to google it since i have seen the rumour repeated many times but don't recall seeing anything substantial and here was ny first hit...
Terrence Howard "difficult" to work with, was highest paid star of IRON MAN?
Finally we are starting to scratch against the surface of mystery that surrounded the sacking of Terrence Howard from IRON MAN 2 which the trades quite conspicuously at the time said was for pay demands.
Entertainment Weekly report that there were two factors in Marvel's decision to let him go. The first was Terrence Howard's "difficult" behavior on the set of the film. They claim that Jon Favreau got so frustrated with Howard's attitude and performance that he spent way more hours than he should have chopping and basically minimalizing his role as Col. Jim Rhodes from a big character, to a supporting player. Another problem was that in the early days of casting, Howard was brought on to the film when no other stars had signed a contract. Marvel, not expecting to get the likes of Robert Downey Jr, Gwyneth Paltrow and Jeff Bridges for the movie, probably offered Howard too big a contract to sign on to secure the first big name for the film.
By the time it was evident that the top Hollywood names were interested in joining this comic book property it was too late for them to negotiate. Leaving Howard, with some of his performance on the cutting room floor, as the highest paid actor of the film even though he had such a small part.
Edit:
Wow, just red this and TH is a very troubled man.
The dark side of Terrence Howard