The creators have talked about avoiding the cliche of the super-powered woman going crazy because of her emotional pain, which is why I expect there's more going on than just Wanda being behind all this.
Especially if they still want to portray her as a hero afterwards.
Not to mention the only members of the team Wanda and Vision seemed close to were each other so who could you reasonably bring in who would have an effect?
I guess there's Clint but he's probably in his eighth retirement.