Among the top clubs, I've found that the Board only ever block transfers of targets for whom too much compensation has to be paid for termination of contract. Or, in some rare cases, club legends. Otherwise, you're pretty much free to do as you will. Difference was, in FM14, you could do anything, and squad wouldn't give a ****. Only the supporters would be unhappy, devastated w/e (take your pick), but that didn't affect your job status.
In FM15, players have lots of opinions, and if you don't assuage their concerns, they revolt, and the squad revolts with them. It snowballs into something big. So more realistic. Damned inconvenient, sure, but realistic. What I don't like, however, is senior players complaining about some reserve players being sold, which is just irritating.