We can talk about how good Azhar is and all the runs that he has piled up, but the fact is that given his playing style, he has never put Pakistan in a match-winning situation and probably never will.
It is not a coincidence that almost all of his big innings over the last year have not proved to be match-winning. Yes there are other factors as well, e.g. our insipid bowling, but from the perspective of the opposition, the longer Azhar stays at the crease the better it is for them.
Furthermore, moving back to number 3 will only compound this problem.
As far as Yasir is concerned, he is a decent spinner who has been made to look like a world beater in this attack because he bowls a lot of overs and doesn't have to share his wickets with others. We all saw how helpless he looked outside his comfort-zone last year, and was one of the chief architects of the 5 consecutive defeats in Australasia. He is good, but quite not very good. Certainly much more impactful than Azhar though.
If these two are our so-called world beaters, then it is fair to say that our current ranking is a very fair reflection of where we stand as a Test team.