Wanda Maximoff has always been a controversial character. Her first appearances in the X-Men were as a villain alongside her brother,reluctantly in cahoots with the villainous Silver Age Magneto and his Brotherhood of Evil Mutants. Later, she appeared in the Avengers. In an unprecedented streak, or creator Stan Lee made the decision to replace most of the former lineup of the team with characters that had initially appeared as villains,including Wanda, her brother Pietro, and Black Widow,and Hawkeye.
Source: blastr.com