While this is true, I've been on 20+
DCL cruises, only 3 of which had issues with disembarkation. This is usually a delay in US Customs clearing the ship, and when that happens everything backs up. Normally, we walk off the ship (sometimes there is a delay of less than 5 minutes in a line because they now restrict the number of people in the terminal--they will hold you on the ship for a few minutes if the terminal is too crowded). Then you claim your luggage if not using the onboard check in system on a participating airline. I believe that the onboard check in is new since TV guy cruised DCL, and it has markedly decreased the time/crowds in the terminal as those using onboard check in are directed another way thru Customs and to the bus. You grab your luggage, porters are there to help if you wish and the luggage is in color/character coded areas based on your cabin number. Then you stand in line for Customs--2 separate lines (US citizens and non-citizens). The line is generally 10 minutes or less. You spend 30 seconds with a Customs agent, and you're off to your transportation to MCO.
If you use onboard check in, you will leave the ship and be directed to a different area of the terminal (there is a CM with a sign as you enter the terminal). You'll bypass the luggage area and go directly to a rapidly moving Customs line. The whole process is very easy. It generally takes me no more than 15 minutes from when I decide to leave the ship till I'm outside.
That said....there was the cruise when Customs didn't clear the ship till after 9. ALL the guests were lined up in the hallways, and it was a total mess. I've also had clearances that came thru at 8:30 while I was at breakfast. We just stayed in the dining room till about 9, and by then the crowds were gone.
Disney has done several things to make the disembarkation go more smoothly in recent years, probably in preparation for the increased number of passengers on the newer ships. It's working very well.