I don't think Wanda will be the cause of the x-gene, simply because the multiverse is soon coming into play. Somehow the x-gene will be a repercussion of that, not Wanda.
I must admit, I didn't quite like this.
Wanda is (or was?) an Avenger, and their purpose was to protect people and their free will and now we have Wanda controlling people?
Emotionally pained or not, that's just not right, and I'm surprised further that her brother (wherever he's from) is okay with al of this.
Makes you think a bit about the future too, in the sense that if Wanda is this powerful, how would she hold up to the likes of Thor or Carol, and if Wanda is in the next Avengers film, how much of a threat will the next villain truly be if Wanda can pull all of this off.