You said that X-fan anger at Scarlet Witch is mostly not directly to the character, and I partly agree, but I've also seen a lot of fans who are angry at the way Uncanny Avengers had her trash-talk the X-Men and make a speech about why mutants don't have their own culture and so on. Maybe you and Remender decided this was worth it, but I think that since her return the character has often been written in a way that almost invites antagonism from readers with a strong love for the X-Men.