Turkey is about to acquire S400 and perhaps there are also local developing systems similar to Irans bavar373 not made public. Pakistan also possibly has low numbers of Chinese HQ-9 for nuclear installations and similar since those areas would be very unprotected against a sudden attack otherwise. What would be wrong is neglecting the sams in favor of airforce or vice versa. It would be like a boxer with good punches but its guard down. If for example some country claiming to be your friend and offered to provide aircraft in case of your imminent need but arguing that you allocating budget to high altitude sam systems would be a waste against you advised by your enemies then be sure that they dont have good intentions but to lag you behind and leave you open-vulnurable to others.
Spada sytem seems good to counter cruise missiles and low altitude targets including super sonic cruise missiles but I dont know if its engagement envelope fits to target brahmos though. It can track 12 targets which is suitable against a saturation attack. As I know previously more than a decade ago you started a2a missile development jointly with China for Sd10 missile. There were also a2g missile news (H2, H4) around that era developed by Pakistan based on a2a missile development. So Pakistan can develop this type of ground based amraam system.
For subsonic cruise missiles you have Hq-7 FM90. It has a cheap missile suitable for the task and is enough to protect mobile columns but to protect airbase or nuclear station from a saturation attack a system needs to be developed having a radar that targets and guides many missiles to multiple targets(10+) at the same time. The radar and guidance is difficult but missiles would be cheap in that case.
Hq 16 can provide medium range cover for all targets be it cruise missiles or aircraft but needs to be coupled with FM90 to protect better against anti radar missiles.
If you have good shorad you can compensate the lackings of a modernized older long range sam. So instead of copying S300 I will later make analysis about modernising longer range systems like S200 or Sa2 modernized versions