Gien

Nah it's more like Oda is working to fix plot holes in meaningful ways, you have to remember Shanks sacrificing his arm for Luffy was something that happened so many years ago before we reach this point in the manga, hell I was a kid back then. I doubt back then Oda had fully fleshed out his plans for one piece, the existence of Haki and so many more. The recent reveal about Shanks past only made that plot hole more clear so Oda needed to fix it, since if Shanks had been a godknight before that fateful day he rescued Luffy, it means he was already one of the most powerful fighters of his time, at that point even if he was being sentimental he shouldn't have lost his arms into something so weak, that is simply illogical and stupid, but shanks character is the farthest from those 2 words, so Oda needs to give shanks a reason to let him get his arm removed to fix the plot hole