Rome had a north african emperor. we don't have pictures of him, and 'race' is a modern invention. Ancient people didn't care about that. to be worried that a model does not reproduce white roman emperors is to be worried about its replication of popular images of roman emperors over the last 100 years or so. In this case it is not accurately replicating popular images of roman emperors, and if that's good or bad is up to you. but to say it is not accurately replicating roman emperors themselves? well, its not doing any worse.