Originally Posted by DrCosmic
If they've had their own solo movies, or appeared in someone else's, then you don't have to explain *how* they got their powers, just what their powers are and their personality, and all that has to fit with the movie's storyline. That's why you can't do an origin with Avengers, cuz there's no time to spend on a separate storyline that doesn't tie into the main storyline. There's barely enough time to give six people great character moments and action moments and serve the story. There's simply not enough time to do the same for seven or eight people. At least, not unless we treat them like Hawkeye, in that they aren't really integrated into the team's social storyline, don't have their own character arc, and they don't really have much in terms of abilities, to show off, so we can show it all in just a few minutes. I don't think that works for Black Panther, Ms. Marvel or Vision.
That gets a bit tricky though. Not every Avenger will have their own movie and I know a fair few people will complain if some random person appears in somebody else's movie and has such a major moment as the time they get their powers. I know the Widow got a bit of flak for this in Iron Man 2.
I agree with what you said about giving the others enough time to develop. I think you can make it to seven though. Any more and it's too much.
Take for example if Ms Marvel is the new character. She brings a new dynamic (and more diversity) but most of all, if the storyline has a cosmic essense in it, then you can write in that Special Agent Carol Danvers was investigating first contact with an alien race when she got her powers. The Avengers are called in to interview her and investigate the object. So that works for the story.
Seven is the max though. After that, you'll need to start dropping Avengers.