Amir is overrated - he is simply decent, neither poor nor outstanding. He will be economical most of the times but not penetrative enough to take enough wickets. Good batsmen can see him off, and he doesn't have the pace and more importantly, the skill to force the issue.
Even in the last series he started off with a 6-fer, but he was back to his innocuous self once the WI batsmen adjusted him against him. Simply a step below the best pacers in the world i.e. Starc, Rabada, Anderson, Boult, Broad, Hazlewood etc. He is more than a year into his comeback and we have seen both his best and his worst. It is time for people to accept the reality that he is not the bowler they thought he was, and it is time to stop making excuses. That will automatically happen if we lower our expectations, and I have personally reached that stage now.
Abbas is another bowler who is neither exceptional nor poor. He will give you a 6/10 type performance day in day out, without making much of an impact. However, he is certainly better than Rahat and Imran. As far as Wahab is concerned, he is also a 6/10 type performer but unlike Abbas, he will be 8/10 one day and 4/10 the next, so the net effect/impact is pretty much the same. Unlike Wahab, Abbas won't bowl match defining spells but he won't bowl Pakistan out of the game every now and then either.
Hasan Ali certainly has the most potential out of all our pace bowlers, but he is a rookie at Test level for now. He bowled an outstanding spell with the old ball the other day, but it won't yield him many wickets if he doesn't increase his pace. I don't agree that he is too short for Test cricket, because with a little tweaking, he is capable of leading this attack.
As far as Yasir is concerned, he is by far our best bowler and the only match-winner in the team right now. However, he is also a bit of a match-loser. If the conditions suit him, he will bowl you to a victory 9/10 times provided that he has runs to play with. However, if the conditions don't suit him, he is almost equally likely to get hammered like there is no tomorrow. Since his debut, Pakistan have only drawn two matches match in which Yasir has played, the first Test in Bangladesh and the second Test vs New Zealand in the UAE, which is a fair reflection of the performance of our stock bowler.
In almost all the matches that we have won, he has been pretty much our best player, and in all the matches that we have lost, he has mostly been one of our worst -if not the worst - player(s).
In summary, it is a middling attack which will do well in favorable conditions because of Yasir, and it will get thrashed in unfavorable conditions again because of Yasir and the others. Hence, it is not an 'ideal' attack and we are setting ourselves up for disappointment as usual with such lofty statements.
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) and we found the right combination already.. 
