I've thought for a while that commuter rail lines:
Along the freeways: 35, 10, 281, 151
Between big retail spots: Downtown, Quarry, Rim, Stone Oak, 1604/Bandera, Forum
Big Business: Rackspace, USAA, Downtown (again), Amazon, Lackland AFB, Kelly AFB, Brooks
And new parking areas near big residential centers: Bandera/Tezel, Helotes, Boerne, Stone Oak, Great Northwest, Brooks City Base
Along with parks renovation, school improvements on the South Side and small business incentives would make San Antonio the best place to live in the country.
There's a lot of potential here.