5. Harry Kim
I really and truly think that if you were to find a Star Trek dictionary and look up the word "useless" you would see a picture of Harry Kim. What did he do in the show? He was a foil for Tom Paris, kind of his sidekick, but what did he ever do on his own? And how could he, on a ship like Voyager with all the adventures they had, still remain an ensign as they found their way home? It just doesn't stack up. In one of the episodes they actually killed him off --- I must admit, I cheered. But before I could break out the bubbly, lo and behold! They had an alternative-universe Kim to replace him. And
he never did anything, either! At least in NextGen Thomas Riker was a totally different person to Will. This guy was just a clone. And in true Voyager fashion, the reset button was pressed and nobody ever mentioned that "this" Harry wasn't "their" Harry. I don't think the original one even got a funeral: maybe that would have been in bad taste, considering "he" was still around. But why didn't they leave him dead? What did they achieve by bringing him back?