I strongly disagree, it is very feasible, this is what it will most likely look like:
1. Luggage will likely be pulled by an existing luggage delivery service like Bags, etc. and delivered directly to WDW resort as it used to with DME..
2. You take the tram from MCO main terminal to the new Intermodal terminal where the Brightline station is.. Not to mention, any flight that arrives at the new Terminal C will have direct access to Brightline without even having to board a tram..
3. You board the Brightline train towards DS, you sit back, relax in comfortable seats, on a modern smooth sailing train, maybe even enjoy an on-board beverage or snack while you are at it.. No having to deal with traffic, no traffic delays, you will zoom by congested roadways and smile knowing you made the right choice..
4. Upon arrival at DS you will simply get off, find your shuttle transfer to your WDW resort and of you go..
How is this putting a peg into a square hole?