Has to be - what are the options? 5'7" Fahim? 5'8" Hasan? 5'9" Shinwari? 5'10" Raees? 5'11" Amir? International teams have players outside PSL in their top 3/4 - batsmen will start taking guard a meter in front of popping crease against that attack - 50% swing gone.
There are options indeed - 6'5" Tanvir, 6'4" Sohail, 6'3" Wahab, 7'1" Irfan, 6'2" Rahat ...... unfortunately everyone is in their mid to late 30s by next year, having born at least 4 to 7 years old already in mom's womb - sad but bitter truth for a WC where teams will be playing confirmed 9 games, may be in 29 days max before the all important KOs - NOT SUGGESTED. Trust me, not suggested - ICC is getting smarter - their medical staff will cross examine before any "injury" replacement.
15 months is more than enough time - it took Hasan less than that to reach top rank, BECAUSE whatever it's hidden in his certificate, guy was still called at a time when learning curve was stiff and body was ready to take the work load. So was Amir - bowled in 10 Tests in NZ, AUS & ENG in 8 months and bowled like a champion for 40+ overs/Test - because he was 18/19 - even if he was born as 10 years old for the sake of saying, still in his mid 20s......
ODI's are different ball game than Test - it doesn't take fast bowlers that much maturity to deliver in ODI. Imran won a WC (interestingly of same format) after losing his most lethal pacer 3 weeks before, himself struggling with shoulders - simple reason was that he had 24 years old Wasim & 18 years old Aquib who ran, and ran hopelessly for him (Wasim bowled over 50 wides & NOs, but, boy his legal ones were as venomous as anything I have seen to our Cobra dance) and 19 years old Mushi who bowled like a 25 years old in the middle overs. In current context, Imran probably would have called back Sarfraz Newaz, when Waquar got injured, because of lack of talunt!!!!!!!
I haven't played much cricket and I know very little, but I do know the history of the game, how the game is developed in each country - IND, PAK, AUS, WI, ENG ...... particularly PAK cricket, how it functions at it's highest potential. If I were in charge, I would have dropped both Hasan & Amir till the AUS ODI tours and played every ODI & T20 with Afridi, Fahim, Amad and may be Arshad and another kid (even Umaid, guy will be 35 and probably born like Imran - grew 2 inches between official 18 to 21) - if required, make ZIM tour 7 game ODI series and call IRL/AFG in UAE/PAK for 10 games triangular - even in AUS/NZ series - Amir/Hasan plays alternately - only best possible XI (pacers' combination) plays in those last 10 ODIs in SAF & ENG - that's a proper WC preparation. These WIN/BD/ZIM/AUS T20s are jokes - more damaging than preparing for WC.