Of course you would. Conveniently, the actor you want wouldn't be weeded out by it. I don't believe that Cavill being British will disqualify him from running. It might mean that some execs at Warner Bros. will be biased against him, but if the director wants him in the role I don't think they're going to get in his way. Keep in mind, he was almost Brett Ratner's Superman, and him being British is not why that project got scrapped. With Captain American the prerequisite that the actor be American makes sense since he's Captain America, but with Superman it's not necessary, especially since he's an immigrant anyway.