Let me put it in that way.
AD FIA has no official residence.
AD FIA has no govt vehicle.
Promotions in FIA are deadly slow.
AD FIA can never get to the top command, as DG FIA is always from police.
FIA is fully politicized .
FIA comes under ministry of interior meaning it is not independent.
Ironically AD FIA has no official security.
The cases you are talking about dealt by FIA are politically motivated like exact scandal etc.
I had also served as Jail superintendent, 99% cases (except politically motivated) dealt by FIA had minor nature and exploiting middle class people (mostly for money) ie shopkeepers, medical stores, clinic etc, They can not start any high profile case unless recommended by Interior minister, which always ends in some kind of Muk Muka.
FIA , in order to arrest anyone or conduct a raid, they can't do it without Police help. My friend who is AD FIA, recounts me an incident that how he and his subordinates were detained by shopkeepers when He conducted raid on currency exchange market.
AD FIA, Inspector FIA has no official weapon, by rules (I myself was shocked to hear it).
More importantly, FIA is so undermined by judiciary (pertaining to their political involvement) that in most cases they need judicial warrant to take action against anyone.
And it hurts, when you watch D.AD FIA in your neighbourhood always complaining about his job nature, facilities, promotion and most importantly when he told me that
"may D.AD FIA hun, na meray pass sarkari gadi ha na he driver, sham ko office sy anay k bdd bachon ka hair cut krany sy lay k subzii tak mujhy jana hota har jaga, aur uper sy security threats b han mujhy"
Dude, I know you want to be some kind of Robbin hood, I always wanted to be before joining govt service
but your Robbin Hood character will die itself when being an AD FIA, someone abuse you, drag you or... and in return you can't do anything, and you department never stand by you (Not like Police department which always stand by its employees)
Ask me more, i will tell you more
i have lived 3 years of my life with law enforcement agencies, i know every bit of it. (as prison department is in core communication with all law enforcement agencies, NAB etc)
BUT IF YOU ARE A NORMAL PERSON LIKE ME, WHO TAKE FIA JUST A JOB LIKE ANY OTHER GOVT JOB, THEN ITS OK, BUT A ROBBINHOOD IS GOING TO SUFFER.