It's kind of hard to articulate, but...
Worm and My Hero Academia have altpowers up the wazoo. Taylor and Izuku have been given every single power under the sun--both of them have fics (with trope pages!) revolving around the Iron Giant, for crying out loud. That's because the powers they have might be iconic, but aren't really important. What's important is who they are and what they do.
If Taylor had different powers, or if Deku had a Quirk, there's not a doubt in my mind that, changing nothing else, they would make all the exact same decisions. Taylor may not be Skitter, but she's still going to escalate everything way out of proportion. Midoriya may not have One for All but that won't stop him from breaking himself into pieces if it means saving one person.
With Luffy... Granted, we only found out about the Nika stuff relatively recently, but I can't imagine him without the Gum-Gum fruit because it's such a clear expression of who he is! He's a goofy slapstick cartoon in a shonen anime, and his elastic powers are such a perfect match for his personality--and the Joyboy such a perfect encapsulation of his truest self--that to give him something else would be to fundamentally change him in a way that taking QA away from Taylor doesn't.
As for Ash and Pikachu? They're brothers. Two halves of a whole. We've seen Ash bond with all his pokemon at one point or another, but he's never had a bond with any of them like the one he has with Pikachu. Not Charizard. Not Infernape. Not Greninja. They're all part of his family, but not one of them compares to Pikachu. Making it so they never meet is like a piece missing from the great puzzle of the world. It's not just wrong, it's incorrect.
titsay
theartofmadeline
yousharknotpass
jbbartram-illu
germansingergirl
kaledo-art
