I forgot to mention that Tri-Rail would also like to initiate commuter rail service from the under-construction downtown station using the FEC tracks. That would give them two north-south parallel services.
What is lacking, IMO, is good rail service to the south. There is Metrorail to Dadeland [SW 95th] and a busway south from there with some Park 'n Ride lots along the way, but people don't really like to have to "change", especially commuters.
In short, Miami transit planners have been asleep at the switch, and now traffic gridlock has come to the fore as a source of real annoyance in try to get around the area. We are not talking only of limited entry expressways, but also street arteries like Galloway Road that are just awful during rush hour.