Plus it seems like they want to streamline things and have characters who had active status in the x-books be mutants. It just didn't make much sense for Wanda when she hardly ever dealt with any mutant issues. It became nothing more than a fact on her character sheet.
She's also been retconned enough. Too much already. Keep her parents the Maximoffs. It's the surname she's kept the longest and the family that raised her regardless of past familial links she's had. Keep her as a nexus being that was blessed by Chthon at birth. That and her practicing traditional magic is enough power origin for her.