Agree very few, if any stops between downtown to downtown. I would compare it to the Eurostar between London and Paris. There is one stop on either side of the chunnel (Dover UK, Calais FR) and they are building another just for the station near Olympic park. Plus there are non-stop options as well. Only a few trains a day stop at the alternate stations. If I were designing I'd have maybe a stop for The Woodlands, and possibly Huntsville, and only stop there maybe twice a day, while the rest run non-stop. If you want to add other options to DFW, have a direct line connection/continuation either into FW or up to Frisco/Plano at slower speeds, but the main terminus being city center Dallas.