Well, for placing it lower on the preference list, I have given you my reasoning.
As for placing it on higher merit order, someone who has opted it as his top choice would be best able to comment. Nevertheless, something on these lines should go:
- FSP is a relatively cleaner service (clean from fiscal corruption, clean from abuse of 'raw' power i.e. thana kacheri, clean from political influence)
- FSP gives the opportunity to enrich oneself intellectually through exposure of different cultures, places and people.
- One needs to have an instinct towards people-to-people and diplomacy skills to opt this as one of the choice.
- Excitement to travel around the world and talk about Pakistan.
- Ability to better the image of the country and possibly help convey Pakistan's point of view at different international fora. At the same time, bring a reality check to the Foreign Office.
Hope it helps.