For what its worth, I have been reading on this forum regularly for over a year the horror stories about immigration/customs at MIA.
This past Sunday March 30th arrived at MIA at 315pm in the afternoon on AA from Port Au Prince Haiti. Total time from airplane to my truck in the Dolphin garage ? 15 minutes! Quick trip on the monorail, walked right up to a kiosk, then directly to the doors exiting from customs. Waited there about 3 minutes, talked briefly with a customs officer, then not being flagged for further inspection made the brief walk to the outdoor area and over to the Dolphin garage.
Needless to say, quickest international exit from MIA in over 30 years of using the airport as a South Floridian.
So what's the problem ?!