The Rejects:
1. The Penguin
I, personally, have never been able to take the Penguin seriously as a primary villain. Batman Returns was his only film appearance and is only passable in Tim Burton's Gotham City, not in a hyper-realistic world that DC is going for. For the uninitiated, the Penguin is Oswald Chesterfield Cobblepot, a Gotham criminal who has a deformed nose, hands and feet that make him resemble a Penguin. Operating a nightclub for the seedy underbelly of Gotham, the Penguin is largely left alone by Batman as long as the Penguin snitches every once in a while. While a feature film appearance by Cobblepot could work on a secondary or cameo level, as a primary villain, he just doesn't work.