Okay we have Epic Fail Devil Fruits, and now its time for the characters.. Oda's creativity is amazing, every character is awesome okay... BUT.. They are some characters that show that Oda got bored and just rushed to make them..
My choice is Chess and Kuromarimo and like that: Chessmarimo..
Other possible choices: Alvida, Chew, Fukuro, Igaram, Nero
I find them dull and without any sign of imagination...