The reason for our fast bowlers not being good is that our domestic circuit is not good enough. Ramiz Raja under Tauqeer Zia with unlimited powers (which come with dictatorship) changed the nature of pitches of domestic cricket.
When the wickets were flattish in the 70s, 80s and 90s we produced bowlers who can run through teams with reverse swing or extreme pace or spinners who had 3 types of googlies or doosras. Why did this happen? Because they couldn't get wickets with just bowling seam ups. They had to find different ways.
When wickets are green we have produced medium pacers who try to hit a length and the ball/pitch does the rest for them. When in international cricket this doesn't happen they struggle. From Wasim and Waqar we are down to Ehsan Adil and Imran Khan.
Similarly for batsmen, we had stroke players in plenty. Now we can have batsmen who look to survive long periods, play few shots, and wait for ball to get old, pitch to dry, spinners to come on. Azhar Ali, Sami Aslam, Imam ul Haq, Fawad Alam, to a degree Asad Shafiq.
If Pakistan wants to play Test cricket like the 90s we have to go back (to a certain degree) to the system that produced such unique talent.