There, I said it.
His shtick is always the same, he's completely one-dimensional, and every time he tries to carry an episode, it fails miserably. Who really gives a flying crap about Zoidberg's film director uncle?
To be completely fair, he is credited with some of the funniest jokes in Futurama history. But for every Zoidberg Jesus, there's five or ten "Zoidberg is so poor" or "Zoidberg eats everything" jokes. He's a little like Ralph Wiggum on The Simpsons, except on that show, Ralph Wiggum is the 35th most important character.
In short, Zoidberg is bad and he should feel bad!