The A-5Cs were the best we could afford in the 1980s as the PAF set the bulk of its funding towards new F-16s. I suspect the goal was to use the A-5Cs as a stopgap until we had enough F-16s to allocate for the air-to-ground role. In fact, the PAF foot the bill for integrating the ATLIS targeting pod to the F-16 and tried securing other compatible munitions, especially the Penguin AShM.
In the 1970s, the PAF had sought a dedicated attack fighter. It selected the A-7 Corsair II and was in negotiations with the US for 110 A-7s. However, that deal fell through due to America's concerns about our nuclear weapons program. By the 1980s rolled around, a single multirole workhorse (i.e. F-16) was a better idea than specialized aircraft.
tbh I think the real shame was the Italian-Brazilian AMX. It came 10 years too early. Had the AMX entered production in the 2000s, I think the PAF would've acquired it (instead of Mirage ROSE-II/III) for precision strikes, SOW deployment, CAS, CT/COIN, etc.