the myth that if a valid visa for USA / UK is stamped on Pakistani passport the visa for countries can be a 'brush your teeth' easy task.
For Pakistani passport holders even a Bangladesh visa requires 3 weeks processing and 12 point compliance to file an application.
after application is submitted with requisite paper work and Passport is called-in the travel history over the passport pages & supporting bank statement make 50% of the case, 20% depend on the bilateral relationship between 2 countries and final 20% for a yes or nay depend on personal 1-to-1 interview of the applicant. 10% chances are that with a valid visa stamped the country immigration officials have right to decline you an entry at their discretion - My home minister have UK & US visa since even before our marriage, her 1st russian multi entry visa was stamped in 2002, the last one expired in Feb 2013 and its been twice she was declined with a visa for russia. she got Schengen visa applied at Netherlands consulate, KHI without an interview and I was declined after interview.
In General Airlines accommodate passengers for a short stay E-visa upon arrival at their central hub when in transit,From Pakistan airlines like Turkish, Emirates, Cathay Pacific Singapore Airlines, Malaysian Airlines practice this as routine.