In Ang's defense, his Hulk worked for what he wanted. He treated it as an alter-ego of Banner, a release of some sort for him.
Where as this Hulk seems to want to get the point across (I mean, look at that expression on Norton's face while strapped to that chair, as well as his worried almost terrified look while captive during the campus scene before he turns!) that Hulk maybe a part of Banner, but they are trying to convey an uncontrollable beast this time around.
Rage is playing a big part in TIH, while Hulk seemed to get a bit cranky in 03, he's straight up crazy in this one. (Though thankfully not Ultimate Hulk crazy.)