At both of my old airlines, we never used to have FD briefings. It would go as far as an introduction from the Flight Crew and that would be it, unless there was anything special to say about weather/delays etc.
On a long haul we would get a more detailed briefing from them: Flight times, delays, slot time, when to meet to go to a/c and any weather problems (and what time to meet at the bar lol) but that's as far as it went.
I don't think FD briefings need to be too much. I think it needs to concentrate on things like on time performance, weather and flight times.