Changing the actor wouldn't change much of anything. Worst I can say about Cavill with the material given is his American accent can be better. Personally, I thought Chris Evans' Cap was decent in The First Avenger and kind of bad in Avengers. Winter Soldier is where they finally nailed it. Question is if Cavill will get the opportunity.
Man, there are sometimes the casting lines up but the material lets them down. Josh Brolin as Jonah Hex should've been dope. Or Mark Strong as Sinesto, in the sense that he was great in a bum film. Shame they likely won't bring him back.