As much as change would be great, it could also be a shot in the foot. Rizwan becoming captain would ensure his selection indefinitely at a time when Pakistan are producing very promising openers (Haris, Saim, Fakhar, Abdullah).
Shaheen becoming captain at an age where he should be mastering the art of bowling will probably take his focus away from improving his bowling. He still has a lot to work on bowling wise and it's best for Pakistan in the long-term that he works on this before anything else.
Babar has been pretty uninspiring as a leader but he is the biggest sports personality in Pakistan, even if his performances dip to zero he isn't being discarded from any format. He's probably the best and only choice Pakistan has.