PCB has done a good move to hand over captaincy to new Salman Ali Agha and dropped Rizwan along with Babar Azam. With time Salman will learn and PCB will be able to prepare a good team for T20 world cup next year.
No I don't think it's wise decision to replace Salman Ali agha with Rizwan as a t20 captain, no doubt Salman deliver some ordinary performance recently in some of ODI format matches. but when it come to t20 his statics were below average player and he hasn't proved his captaincy skills ever but compared to him Rizwan does several times for PSL franchise Multan Sultan several edition and already won a title too. So I believe PCB will regret on his decisions as still I believe Rizwan can goes ordinary, but if it really obligatory then instead of Salman Muhammad Haris will be best option to replace as a captain as he has won some vital achievement for his team under his captaincy.