If Steve Rogers wants to dance with Peggy then also that promise was fulfilled, so why didn't Steve want to become Captain America again?
Steve didn't want to become Captain America again. He's served his time AND managed to have a full life with Peggy as well. It's time for someone else to take over.
Consequently, there was no need to make him young again (...
Ultron believes that humans are the problem, and thus they cannot be a part of the solution. He says:
I know you're good people. I know you mean well. But you just didn't
think it through. There is only one path to peace... your extinction.
According to Marvel.com:
Ultron decides that the best way to save the Earth is to destroy all
the people on it to ...
Her memories hadn't been tampered. In the movie, Kree civilization is not shown to have ability of tampering memories. In the first scene she remembers that she was bleeding. Now if i dream of bleeding i would imagine the color to be red because that's what i know my blood color to be. She imagined the color to be blue because that's what she knew her blood ...