1) Quicksilver Survives – Avengers: Age of Ultron
The death of Quicksilver in Avengers: Age of Ultron was something of a shock, which is exactly what Whedon was aiming for. He wanted to give the film a “war movie” feel where not everyone made it out alive.
However, he nearly changed his mind and had the speedster recover from his seemingly fatal shooting – he actually shot a version of the line-up of the New Avengers at the end of the film which included Quicksilver. In the end, though, he decided that he shouldn’t pull an Agent Coulson, and left him dead.
At an earlier stage, it was also Whedon’s intention to throw in a couple of other characters into that final scene that we haven’t met yet – including Captain Marvel and Spider-Man. Both have movies coming in the next couple of years, which Whedon wanted to set-up with their appearances here.
However, Captain Marvel hadn’t been cast yet and the deal with Sony for Spider-Man was not quite finalized in time for the movie, so Whedon wasn’t able to put it all together as he intended.