Butler or Middleton would have been my top target in the offseason if I were the Sixers. On court, Butler should be a great fit on offense and defense. He'll reduce Embiid's offensive load and make the Sixers much tougher at the end of games. They really needed a top notch shot creator. Between Embiid and Butler, they'll be getting to the free throw line a lot.
Butler's personality is the big question in my mind but I think that gets alleviated by the Sixers winning and being defense focused. There's a huge difference between playing with Embiid and Townes.