Yes, WP is somewhat weird. I got one no problem for Romario (the really good DR) in my first season at AFC Wimbledon (League2). Just when I moved up, before his loan was up, I offered 500K, accepted and then WP was refused even on appeal. I tried again and the second time of asking WP was granted on appeal.
The work permits in FM are given out a hundred times more often than they would be in real life imo.
Depends how far down the leagues you are playing. If you are playing in the BSP/N/S then after the first season you can find dozens of players from all over the world that have left BSP/N/S teams as they can't get work permits and never will despite playing for years in those leagues before the game starts.