I have a theory that the way someone does code reviews will say a lot more about them than a white boarding problem. 1) You'd get a good sense of their attention to detail and ability to think about code without actually running it. 2) It could cover not just bugs/edge cases/performance issues/depth of knowledge, but also patterns and best practices. 3) You could see their communication style and their ability to offer criticism without belittling people.
However, if the code in question is solving a highly self-contained problem, I think this could be a good part of the hiring process.