Joss Whedon specifically sought Aaron Taylor Johnson to play Pietro, and considered Saoirse Ronan before ultimately going with Elizabeth Olsen for Wanda.
It also has another complication that in order for Romani actors to want to even play these characters, likely they'd have to forgo the dark magic thing in Wanda. Or at least make it so it's not inherited by her family.
I honestly hope at some point there is a Romani writer that creates characters in comics. So there can be a reference point for what is healthy and what is bad or stereotypical.
Love is for souls, not bodies.
I hate to say this because I'm a big Pietro fan, but I think by Avengers 2, the MCU needed a superhero to die. It was getting to the point that the superheroes in the MCU were becoming invincible and none of the battles had any stakes or consequences for them. So I understand why Feige made the tough decision to finally kill off a superhero. It's just unfortunate that Quicksilver was the first hero to bite the bullet in the MCU.
Regardless of Pietro's mutant status, I think writers at Marvel should take a chance by doing new stories about Quicksilver that are unexpected and different. Vision for a long time was a painfully "one-note" character and Marvel editors let him be totally reimagined a few years back. And the results have been stunning. Even a Disney Plus show is taking inspiration from that series. I think Pietro needs a writer to make him relevant again.
It's fine to have death. But it doesn't have to be cheapened or in Pietro's case not make any sense. Since he can go Mach-5 and catch bullets. Something built up and meaningful is fine. Pietro did not have nearly enough time in the universe for that kind of payoff. It was just cheap emotional manipulation. And one of the worst moments in the MCU, because it's so cheap.
Love is for souls, not bodies.
I agree his death was poorly done and had zero impact on the Avengers at all. The way he went out WAS pathetic and not particularly creative. And really cheap. But I do think it sort of grounded the MCU a little bit. Made the heroes a little bit less invincible. If Hawkeye, War Machine and Maria Hill were killed in that movie, it would have been meaningful. But it's obvious Feige and company had future plans for those characters and none for Quicksilver. But yeah, to kill a character introduced in his/her first movie is a pretty shitty thing to do. Especially if that character is a superhero.
From what I remember from the Week of Ultron, right after Pietro was killed, Tony, Steve, and Thor were cracking jokes about elevators being able to hold the Mjolnir. So yeah, no respect there to Quicksilver fans. I just think Disney didn't want to have a character that another studio was using. Having two Quicksilvers and having them being compared to each other constantly is just something I don't think Marvel Studios was interested in. And let's be honest, it was Wanda that they wanted. Feige and Whedon made that abundantly clear. It appears the two of them were pretty invested in the whole Vision/Wanda thing (surprisingly Markus and McFeely, the Russos, and Waititi were too). That's why I think WandaVision is the PERFECT time for Pietro to return. I don't think it would make sense for him to show up in the Multiverse of Madness. That movie's gonna probably have 5001 characters and I have no desire for a 5 second ATJ cameo. If Quicksilver shows up in WandaVision, he can even have an extensive cameo. Which I would welcome.
Love is for souls, not bodies.