Brightline is not a commuter rail service. It makes absolutely no sense to stop at the convention center for local travel from the airport. Sunrail is the commuter rail service that should be expanded from the airport to the convention center/universal and Disney. Brightline is a great option for people to connect to the major airports and/or go to Disney from the Miami area or Tampa area. Brightline model won't work filling their trains with tourists from MCO to Disney Springs.I know Disney is overall the big destination in the area, but is it possible Brightline makes more sense as transportation from the airport to the Convention Centre and I-Drive area than it does to Disney Springs? I don't know the area where the planned stations would be, but I would think the area is more densely packed with attractions and hotels such that it might serve as a more direct form of transportation to those things than it does delivering people essentially to one corner of WDW far away from almost anything other than Disney Springs.
It always struck me this make the most sense for day trippers from Florida to WDW who didn't want to drive, but Disney doesn't seem all that interested in that market anyway.