I'm sure there are Pakistani's who have migrated to PY before. The lawyer we used to help with our residency had made a comment once to me that he was working with someone on their residency and they were from either Pakistan or Kuwait, I forget which. Anyways his comment was that it was "very difficult" at this time to get the application approved as Immigration was very concerned about granting residency to any national from a country considered "at risk" for being a base of terrorism. Not very fair granted, but his comment was made to express his frustration with the situation. My advice would be to contact a lawyer who currently works immigration issues/residency and ask for their opinion. Good luck!
I saw lot of news of paraguay embassador to pakistan regarding offers of nationalty and free land for pakistani investor to invest in agriculture.. I dont know why people discourage applying for paraguay residency...