I don't think anyone likes the design, just no one has been able to reform it. It's too much work and hassle and requires a lot political stability.
Those who know the loopholes in the system have used it for their personal advantages but that doesn't mean they've created those loopholes. They're just there and as I said, no one has bothered to fix them because it's too much effort and time consuming.
Take the recent EU and India trade deal. It has been worked on for more than 20-years. Pakistan has never been politically or economically stable for that long. Unless this changes, which I think it is finally, then we can expect small improvements.
By now, a Pakistani Government would had been stimulating the economy to hit a 5% target but not this Government. It's so focussed on reforms as it's become a matter of national security.