I'm not really sure how you can say Mark was the better Hulk, given the inadequate role the Hulk was given in Avengers, and from my understanding, that was Norton's complaint about it and why they ultimately couldn't work out a deal with him reprising the role. From everything I read about the issue, Norton was very enthusiastic about playing the Hulk, but also has very high standards for the roles he plays, and just wasn't willing to work with the script as given without wanting to improve Banner's role in the movie, and the studio simply didn't have the time nor desire to work with him on doing that, and so gave the role to Mark, who, in comparison, just seemed kind of an awkward, uncomfortable stand-in for Norton throughout the movie. About the only thing that stood out to me about him and his performance in Avengers was kind of an awkward, shit-eating grin he had going on. Otherwise, he seemed to have the smallest, least significant part in the movie, even compared to Hawkeye and Black Widow, and if I were Norton, I probably would have felt insulted by that as well. I can only imagine how much better the movie would have turned out had the studio actually been willing to work with Norton on his issues with the Hulk's role in the movie.
