This is of course, my personal opinion, but I honestly think Zayn was headed in different direction musically from his bandmates (they weren’t going in one direction). The new sound, and new album, are an overall improvement. Some times you just have to change your sound, not always as drastically as Taylor Swift, but change is a good thing. Zayn had been the token bad boy of the group from the begining. One Direction was created to sell albums, and they didn’t need a bad boy figure to fit the boy band mold or to sell albums. Zayn hasn’t meshed completely with the other since the begining. He was a marketing stunt. It didn’t work out, and he left the band. It happens regularly in the music industry and the fangirls need to calm down.