I was on the Liberty on 12/10 in FLL. I got in line around 12:40 and was constantly moving until I was on the ship by 1:50.
The fastest I have been through an embarkation line was in Tampa on the Miracle. I walked straight into the building, through all the "maze" and was next in line to see an agent, but then got to sit for about 45 minutes before boarding the ship.
Embarkation lines are necessary evils but I am sure there are ways they can improve the lines. In Tampa there were Fun Pass lines which moved very fast but in FLL there was no such thing UNFORTUNATELY. They were not understaffed, just need some tweaking on organization.