I love Brooks as much as anybody (Well, as much as anybody should!) but I hate that line of reasoning. Especially as the most famous similar plotline would be the ending of Close Encounters when the decidedly non-black Richard Dreyfuss ditches his family for aliens. Still, I don't mind it so much these days. We know that if Sisko does never return then Jake will ruin his entire life trying to get him back ala The Visitor. Which would negate the point of that episode and Jake's sacrifice in it.