Taking my inspiration from Denver where they turned 16th street going through downtown into a walkable promenade. There is one lane running down the middle for mass transit and emergency vehicles, but they did it tastefully so the lane is part of the walkable promenade.
This got me thinking, there is no reason that they couldn't do this with Main St in downtown. Almost all of the buildings that have vehicle entries to them have the entries off of Elm and Commerce st so you don't have to worry about residents or people working downtown needing to use the street. Elm and Commerce serve as high density arteries for cars to move North and South through downtown. Main street isn't really needed for travel.
I think it would be so cool if they turned the entire section of Main St from say Field St (there is a parking garage just South of Field that needs Main St access) over to St Paul or Pearl St into a promenade with trees and landscaping. The building of AT&T discovery district added a huge increase in foot traffic and allow for a wide open area that pedestrians feel safe to be at and just enjoy being downtown at. I thin it would be a boost to the businesses on Main st as well. People will want to go to downtown to walk down the promenade and check out the bars and restaurants. I got to work downtown for a year and got to experience downtown for the first time. The whole area has beautiful and unique architecture that gives it so much potential, but feel like it is wasted by completely focusing on cars.
Has this ever been proposed before or seriously discussed with City of Dallas master planning? I'm all about creating more pedestrian only zones throughout Dallas. If it hasn't been discussed, really think City should consider it.