It parallels, certainly, but this wouldn't be Hulk going berserk, just Banner getting fed up and quietly taking off. And I'd say it would mainly be the fault of Tony Stark. I dunno why, but I really think we're going to see in this movie that the honeymoon there is officially over.
Though, the more I think about it, this seems like a better way for him to end the movie rather than start it. This could be my subconscious and eternal desire for a good solo Hulk film speaking, of course.
Hulk getting beaten up by Ultron doesn't really make a huge amount of sense to me, though. Sure, he got killed off in the comic, but the comic also kinda sucked and dealt with weird time travel and brutal murder... probably not going to be in the film. I mean if Ultron goes and beats up Hulk, why isn't he killing Cap, Black Widow, and Hawkeye at the same time? Did they just not show up? Does he have a busy schedule?
It ups the ante, sure, but it leaves a bunch of gaping plot holes. I'd figure it more likely that Ultron more uses altitude and range to make himself a target that can't be smashed easily. I mean, he can fly, right? Hulk can reach the altitudes, but he can't change direction mid flight, so it would be ridiculously easy for Ultron to just never get into any sort of engagement range and keep the fight to only Iron Man and Thor, who wouldn't be able to take him alone. It would be more of a case of Hulk being completely useless in the fight, rather than getting creamed. It also allows for a change in strategy, or the addition of Scarlet Witch and Quicksilver, to change the game at the end.
Basically, if Hulk gets beaten up at the beginning by raw strength, there's no plausible way to overcome that in time for the end. If he, for some reason, can't get to the fight, strategy and planning could fix this.
There's another alternative that would spawn off of the theory that Ultron takes over/is JARVIS... in which case, he would have the ability to build and control dozens of Iron Man suits at once. That alone could serve to spread out the heroes enough and up the ante without having to resort to a devastating unbeatable attack.
tl;dr Ultron out-physicallying Hulk isn't a particularly clever way of showing that Ultron is powerful and cunning and it requires an inordinate suspension of disbelief to come up with a reason why any of the other heroes survive this confrontation.
