I think the difference is that an OP antagonist always makes for great entertainment, think of Sauron in LOTR, Makoto Shishio in RuroKen, Frieza, Cell, and then Majin Boo in DBZ, Father in FMA/FMA:Brotherhood, L and Near in Death Note, etc, etc.
An OP "good" guy makes for a boring story if overused----as Mine and her Pumpkin were.