To start I would like to say this is my first article so constructive criticism is welcome.
I would also like to say I saw others rants about A2:AoU and Made my own theory from theirs
Roster:
Avengers:
Iron Man
Captain America
Thor
Hulk
Black Widow
Hawkeye
Scarlett Witch
QuickSilver
I think CA:TWS will end on a down note, with shield in a disarray and fury fired by shield, and on the run. But I also think It will end with good stuff. I think Cap will sorta remind Bucky of who he is, and then have Cap ask him who brainwashed him and have Bucky say "All i can remember is... Red" and then cut to Alexander Pierce talking to a big figure and then have him revealed as the Red Skull and show Arnim Zola.
Now Bucky is being "unbrainwashed" by shield so he can be trained by shield, but by the time of this movie he is not ready, hence why he is not on the roster
Villains:
Ultron
Red Skull
Arnim Zola
Hydra
Calm your nipples, With Red Skull having complete access to Ulron's Database he takes control, and has Hydra ready.
Story:
As The Avengers are now together fighting small super villains, Red Skull has kept his place undercover at shield as Alexander Peirce. He places Maria Hill as leader of Shield. He places the "Ultron Project" into motion and has the armor built out of a Vibranium/Steel Alloy. Shield tests Ultron as recon drone and send him in to stop potential threats. They see that Ultron is a success and have more Ultron Units put into production. Red skull See's this as his opportunity to corrupt Ulton but need's a distraction. He sends hydra's to "Inhumans", code named Scarlett Witch and QuickSilver to attack a Shield base. As this is Scarlett Witch and QuickSilver's first Mission they are defeated by a small team of the avengers. They are taken into custody by shield and are questioned by Tony and Steve.
As they are questioning them, Red skull accesses Ultron's database and corrupts it turning Ultron evil. Ultron attacks a already weakened Shield and nearly destroys the main base and escapes to the hydra base with the red skull, who makes shield think that Alexander has been kidnapped. Scarlet Witch and Quicksilver feel betrayed by hydra as nobody comes to extract them. They agree to co-operate with the Avengers to reveal the location of hydra's base. As a few of the avengers get into battle with hydra and Zola, Others go to find the Ultron Unit and Alexander Pierce. Cap locates Alexander and as he is about to reach him, he attacks Cap with incredible strength, Cap is confused, He says "I've only seen one other man with that kind of strenght..." Just then, the red skull reveals himself and they fight. the red skull escapes and Cap must return to his team. As they find Ultron, they come to find out he's already done a full conversion, and has already started to access the other Ultron units. as they attack him they almost get wiped out. They retreat to heal
Back at Avengers tower, they have convinced shield to hand over Scarlett Witch and quicksilver. they discuss all of hydra's hidden secrets in exchange for payback, then they get notice that Ultron is attacking Wakanda to get more vibranium, the avengers roll out, weakened, but they know they must stop them, with the help of S.W. and Q.S. (Scarlett Witch and Quicksilver). As they reach Wakanda they find Ultron heading toward the vibranium mound and the Red Skull and Baron attacking a the Wakanda capital, Cap tells the team that he must go to face The Red Skull, he brings S.W. and Q.S. to help, they attack baron and a group of hydra soldiers, and cap goes after Red Skull, in the fight cap loses his shield and does some hand to hand combat with Red Skull, just as it looks like Cap is about to be defeated we see his shield get thrown back to him, we look and see the black panther! and then he leaves, cap defeats red skull and take him back into custody. the rest of the team battle Ultron but he flees with some vibranium, Iron Man chases him and is defeated. Ultron returns to his secret base and makes a new suit out of the vibranium.
The avengers go back to avengers tower to discuss what Ultron will do next. Later Ultron attacks new york with his drones and his upgraded unit calling it "Ultron 2" they attack Ultron with S.W. and Q.S. . They destroy most of the Ultron units as Cap and thor and hulk fight Ultron. As Thor Attacks with Mjornir he discovers that his armor is made of full vibranium. Ultron seemingly "kills" Thor (more on that later)and Cap knows that only vibranium can defeat vibranium, he attacks Ultron, sacrifices himself but creates a compromise in his armor. Hulk attacks the armor and defeats Ultron, tearing the unit to shreds in anger at the death of his teammates. The rest of the team gets there to see Thor is gone and cap just about to die. Then he dies. The teams morns and has a funeral at the new avengers mansion, Where tony has made statues out of solid gold, in remembrance of Captain America And Thor. Then we see Stark walking in a lab, He calls out, we see Hank Pym come out from behind this table with the ant man helmet on it they converse as they talk about what uses Ultron could bring, he hands the Ultron head to Pym and leaves. It cuts to some underground base where we see fury walk in he's talking to someone, Its Steve Rogers! He faked his death to join Fury's underground team, black widow walks in, they talk and it cuts to black
In a mid-credits scene we see Thor in hel,he wakes up to see the enchantress , she will cut him a deal, free him and give him some information, in return for her freedom from surtur,Thor unwillingly agrees, he asks what the information is, she reveals Odin trapped in hel. Cut to black!
Then at the end of the credits we see, from t'challa's point of view, him putting on the mask and looking at the claws, he turns to his fathers second in command, "Do you think I'm ready for this?" The man answers "You're father would want you leading these people." It cuts to a outside view of the palace, zooming out from the doors , you hear " All hail the king of Wakanda!" You see T'challa walk out then it goes to black .
I know a lot of this is controversial and I'm open to other theories.