Well if an MLB stadium is built that far north, I probably won't attend games. I have yet to attend any Austin FC games. It's simply too inconvenient for me to travel to the Domain which I at most go to once or twice a year. Maybe if we had a better rail system (as in rail south of the river connected to the red line) but that is unlikely to happen anytime soon.
I personally pay attention to who is behind such proposals as well, and I don't think I will be supporting this venture even if it was closer to the central core. Simply my two cents on the matter.