I liked Voyager
but I'm still going to answer this because I'm bored. If I were the writer, this would've been the difference:
1. Janeway says, "Fuck you" at least once per episode. This catch-phrase is usually followed by either (1) phaser-fire, or (2) a photon torpedo being launched.
2. Seven of Nine wears a black leather cat-suit. Her hair is long, and is never
neatly upped. She invariably engages in amazing displays of "Seven-fu" and routinely kicks ass. Sometimes she wears really cool Gargoyle shades.
3. Chakotay also has long hair, and is far more stoic. He has animal empathy and can command the beasts of earth and sea and sky. He smokes a long-stemmed pipe and speak proverbs of war. He is rumored to devour the hearts of his slain enemies in order to steal their souls.
4. Tom Paris is a rogue gambler and footpad extraordinaire. He is able to infiltrate even the most seemingly impregnable enemy lair. He rides the shadows, from whence he strikes at his foes the killing blow with the surety of a master assassin. He has a patch over one eye, too. The Voyager is saved at least once per season by Paris' gambling skills.
5. Harry Kim grows a beard by season 5.
6. Neelix is quiet and introspective.
7. B'Elaana fights with everyone on the ship in every episode. Occasionally she will take a swing at Janeway, but Janeway is too awesome. With minimal effort, she counters B'Elanna's attack and renders her defenseless. This is usually followed by Janeway's catch-phrase*, and then a swift jab to the nose. B'Elanna is injured, but has learned new-found respect for her commanding officer.
8. The Doctor remains relatively the same.
9. Tuvok routinely defeats everyone with his logic. He never loses control of his emotions.
10. The Voyager slowly changes over the course of the series. While still retaining its basic hull-shape, it becomes more intimidating as the crew salvages new technologies and defenses along the way. Also, it is metallic black in color.
11. Every episode ends on a down note.
12. The Voyager does not reach Earth. In the final episode, Janeway destroys the ship in order to keep a deadly enemy from reaching Earth via Caretaker technology. The final words of the series are Janeway's catch-phrase, followed by a super-massive anti-matter explosion.
*on at least one of these occasions, Janeway would say, "Next time I'll knock your damn head off."