I'm not mad at all, a little disappointed sure, but not mad. I had hopes for more screen time and I was psyched about the trailer money shot that never happened, but I'm ok with the character arc they've been building.
2008
Banner was desperately seeking a way to rid himself of Hulk and doing what he could to avoid triggering him in the meantime and by the end, he felt like he might be able to control it and turned towards honing that so he could live with his condition.
2012
Banner was in full control at this point, not an incident since Harlem and seemingly living life just doing good with his wisdom while staying off the grid and by the end of the film, he was more or less in full control of directing Hulk's rage.
2015
Banner's control had gone even further and more of Banner remained while he was Hulk, thus the decision to run away influenced by Bruce's feelings about himself before his final transformation.
2017
Hulk evolves into more of his own person and is almost separate from Banner in ways, and both almost interact with one another.
2018
We see the separate identities taken to the next step with them having conversations with one another and Hulk takes a big ego hit by losing to Thanos after being able to smash everyone else he'd ever taken on.
That said, even Thor almost bested Hulk in Ragnarok without infinity stone power, so Thanos doing it isn't out of place in the MCU and I don't have any issues with him getting his ass kicked, especially where it was announced that a 3 part arc was woven through Ragnarok, Infinity War and Avengers 4, so I'm just eager to see where they take things. If Avengers 4 is handled poorly, then I might take issue with IW Hulk.