By far most of the content in all the different FP's are being passed. As the former poster established very well, Taral V, is the worst, with Battle of Ilum following close behind. So many bosses (And loot.) being bypassed for saving a few minutes.
Several minutes times several characters equals half an hour.
Don't get me wrong, I have nothing against killing flashpoint bosses if someone in the group asks for it but I'm not about to waste time if I have people wearing Rakata and higher. Not skipping conversations is an issue too. As was said earlier, use story mode for story. Hard mode is only a part of your daily grind and you should treat it as such.
Avoid unneccessary mobs, skip bosses you don't have to kill, soft cc everything you can and run past. Show love to stealth classes and their soft cc abilities.