Who would want to work for a board that hires and fires coaches like one changes socks ?
Also you have to factor how many options are available to coaches now with the advent of lucrative T20 leagues.
Ultimately PAK (& every other countries dependent on foreign coach) has to build internal capacity. Coach is a bit over hyped position in cricket, because a coach can hardly add so much. Cricket being individual skilled based team game, more than combination and team strategy, it's important that individual skill is improved, for which you need better domestic system.
Within next 6 years, PCB has to plan that their National coaching set-up is completely domestic, may be a foreign physio can be hired but games' core skill coaches have to be raised domestically. That can only happen if PCB integrates coaching regime with the new domestic model. Appoint 30 (6 X 5 : Head Coach, Batting, 2 Bowling & Fielding coach) with 6 teams for long term and invest in their development via ECB/CA development programs during off season - say, a bunch of PAK domestic coaches sent to UK or AUS between June-AUG period for higher level coaching badges. Then there should be a 2nd set up of such (for second XI) and so on. Within 6 years time, some of the local coaches will be ready to take up National roles (not only in PAK) on merit.
For that, first thing that PCB needs is to invest on right kind of people/x-players, at right age and with adequate educational back-ground, and pick people who are passionate, proud about the job. I know, Lap-top coach is a pun term, but modern coaches have to operate coaching software, have to analyse performance data, have to understand modern fitness, diet, conditioning methods .... glaring cricket career isn't sufficient any more to be a top level Coach. Already in Soccer, we have seen top level coaches with Masters level education in Sports science, psychology, physiology or even in simple management - Cricket will also move into that route.
Instead of trying to prolong career, I think it's high time that players like Hafeez, Taufiq Umar, Imran Farhat, Salman Butt, Mo. Asif, Faisal Iqbal ..... focuses on coaching career through self development - there is a low hanging fruit waiting for them.