Indeed. But Wasim's point of view isn't wrong either. Pak still has many T20's to play (probably the most out of the top 6 sides) and therefore it can afford to try out a few new combinations + Top Pakistan Cup performers who have shown to take on pressure well in the PSL as well.
We can always get back to Malik, Wahab etc. But this is the only time we can try out new guys like Danish Aziz, Arshad Iqbal etc..
People always asked for more domestic performers to be given a chance and now it is happening yet some fans complain.
I'm not against experimentation, I'm more against selecting raw players. Mohammad Wasim Jr., Shahnawaz Dhani, and Arshad Iqbal are quite young and haven't had enough game time. When you rush into selection, you carry players who have not been picked apart yet. When a player gets exposed at the international stage, the pressure is different, and they get dropped and have shattered confidence. The point is to let them learn from their mistakes in domestic cricket so that they are a more refined product at the international level.
We can't simply return to Malik and Wahab the night before the T20 World Cup, they won't have had game time and they would be rusty.
Pakistan has tried quite a few middle order options in recent times to fill the gap of Malik. Iftikhar Ahmed, Hussain Talat, Haider Ali, and Asif Ali are just a few names I can think of right now. None have performed, except maybe Haider Ali in that innings against England.
The point is that this is a very important tour for us, if we get a settled team combination and win the tour, it will boost confidence and get us much-needed experience. Some experimentations are acceptable (ie. Babar dropping down to 3 to accommodate Sharjeel), but not a whole lot.
The bottom line is that this is the last tour which Pakistan has to finalize a squad for the World Cup. Whether they return to Malik or not depends on the result of this tour. The same goes with Wahab Riaz and Imad Wasim.
Realistically only two areas must be experimented with, the opening combination (Sharjeel + Rizwan, Babar + Rizwan, or Babar + Sharjeel) and the middle order (Danish Aziz coming in perhaps, Faheem being promoted, etc.)
Personally, I'd assume that our batting lineup is going to be Sharjeel Khan, Mohammad Rizwan, Babar Azam, Mohammad Hafeez, Danish Aziz, Haider Ali, Shadab Khan, Faheem Ashraf, Shaheen Shah Afridi, Hasan Ali, Mohammad Hasnain.
Shaheen, Hasan, and Hasnain looks like a good fast bowling attack from my viewpoint, and Faheem Ashraf along with Shadab would contribute with overs when needed. Danish Aziz can also bowl a few overs, and Hafeez can chime in with an over if required. Enough bowling options, good depth in batting, and perhaps the best squad that we can play with the current players in the squad.