Without having read any of the comics or knowing these characters before they showed up in the movies whatsoever, I can't really complain about any of the casting choices. Some I think worked better than others, sure, but none were that bad, IMO. I think they knew what they were doing, especially if any of those "look who could have played..." articles are accurate. Maybe Sebastian Stan could have been Steve Rogers, but it's not like anyone can actually picture that now; they each absolutely owned their roles.
(FWIW, I loved Taika Waititi as Korg, and I can't bring myself to dislike Je