Ultron... the beginning with no end. Ultron cannot be killed. There is no soul in the metal shell, just pure evil will. Destroy one body and he just goes to another. You destroy his tin body, he gets adamantium. You melt that one he goes to Asgard and makes an Uru one. There is no stopping the abomination known as Joss Whedon sorry, Ultron.
Ultron is the living entity of evil and technology and its a perfect villain for the Avengers, but do you really think that the wireless (lol jokes on no strings on him) AI can be fully destroyed in Avengers 2: Age of Ultron?
No, there is no way. You can only take him far away.
Bruce Banner considers himself a pain in the ass to the team as he has the Hulk counterpart who isn't particularly reliable. As rumored, Bruce and Natasha will have a romance. Hulk will hear the Bruce side of him and his love for Romanov and realize how dangerous he is and how he could hurt her. Now, maybe in South Korea they are at a launch site to somewhere in space (who knows) or Tony has made a Quinjet capable of space travel. Hulk manages to grab Ultrons indestructible body and hops into the Quinjet and has Tony launch it off to a planet he might enjoy living on for the rest of his life. This would be a sacrifice on his part and it would show that the connection between Bruce and the other guy was getting stronger.
This would be devastating to viewers. Bruce would launch off with Ultron while giving him a puny robot smashing. This smashing causes the Quinjet to break in pieces and go off course to another planet, Sakaar. When Hulk wakes up, not as Bruce, he would find Ultron was no where to be seen. Ultron would have fallen out of the ship and maybe land in Knowhere and be collected in the Collector's lair or Thanos finds him.
Hulk would also wake up in an arena and fight as a gladiator for amusement. Then the Planet Hulk (as there is rumored to be another unconfirmed movie) storyline unfolds.
[Guardians of the Galaxy 2](movie:1081113) is going to be a great movie first of all. And what would make it better? The Masters of Evil. That's right. Masters. of Evil. Who would these masters be? Well, we have already seen them. Loki, The Collector, Red Skull, Nebula, and Ultron. But we have seen all these guys and we would be a pretty bored audience.
The answer, Kang the Conqueror and Michael Korvac. This is a way to introduce the Phalanx too as Ultron made them, it could be their army. But you might ask why Red Skull? He is a Captain America villain and I might be assuming he is dead? We'll when the Tesseract showed the cosmic space and sucked Red Skull in, it could have brought him to Thanos as he is thirsting for this power.
The Masters of Evil would all be representations of the Infinity Gems too. Kang is obviously Time as his powers are manipulation of time. Loki is Power as he continually thirst for recognition as a ruler. Korvac is Reality as he is almost a god. Ultron is Soul as he needs one to understand it. Nebula is Space since she really has no home and is just a cold void of a person. Red Skull is Mind as he wants to master it. and The Collector is the Gauntlet itself as he craves to own it all.
Holy shiza, the power sets of those would outbeat a maniac, and a tree, and a raccoon, and an assassin, and a rascal thief. There is no way they could win against a time-traveler, two gods, an assassin, a vibranium AI, a gatherer of powerful objects, and a war-like mastermind. That is why we have Iron Man (who would be searching for Banner as he is a bro), Adam Warlock, Nova, Angela, Moondragon, and Quasar. This adds more unique power sets that can rival the Masters of Evil.
In the end, Loki escapes. Korvac, The Collector, and Kang are all dead. Ultron continues to try to destroy all "incapable" beings (Captain Marvel supporting villain?) The Guardians (Star-Lord, Gamora, Groot, Rocket, Drax, Quasar, Angela, Nova, Hulk, Iron Man, and Moondragon) return to Earth in time to save it from Thanos, not noticing Red Skull has tagged a long to exact revenge on Captain America (who is dead as of [Captain America: Civil War](movie:994409), breaks my heart to say).