Originally posted by Rage.Of.Olympus
There was never any myth, Hulk having a theoretical unlimited peak and a strength that directly grows to his emotional state was never in doubt despite what some idiots say. Unfortunately, Pak pretty much did away with that and apparently Hulk can get stronger at will for no other reason than because. And the holding back bit was horrible, it took so much away from the entire World Breaker concept that was introduced in Planet Hulk and explored further in World War Hulk. There's a reason why it was such a great story, it focused on what makes Hulk great. The last arc however was just nonsensical wanking.
Seems you forgot The Hulk just prior to and during M-Day, when he was on his long road to being at peace with and accepting The Hulk aspect. When the Aborigines taught him to control the anger, when he had already learnt to switch in and out of "Hulk mode".
If anything, the comics were at-sea until Pak returned to the broader narrative and brought it back into continuity. Hulk/Banner being the one entity, Hulk being restrained by the Banner aspect, this is what Beyonder said aeons ago.
Banner doesn't function to just reduce/restrain Hulk's rage/emotional upheavals, he exists to restrain the power Hulk outputs (intentionally or otherwise). When Banner get's angry, his effectiveness in restraining that power is retarded, thus Hulk can go WBH. That's the basic mechanism. Banner's function is to restrain, not to catalyse by getting angry.
So, given that he is now at peace with The Hulk, it's only rational that he should be less anxious about easing off on the breaks, which naturally means that Hulk cuts loose a little more (obviously not too much or else goodbye Earth).