Was discussing this with my father yesterday. There are a lot of reasons that we agreed a football stadium there doesn't work.
Usage:
The stadium would be used for major events maybe ten to 15 times a year...7 games, 4-6 concerts, and graduations. It does not make send to a university committed to spend 300 million plus on a stadium for limited usage. It also doesn't make sense in general to spend public dollars on a football only facility. While a baseball stadium is used at least 81 times, the football stadium a fraction of that. Three series in a baseball season probably have as much economic impact on surrounding bars and restaurants as an entire football season does. Even an nhl/nba arena gets far more usage as there are usually a ton more indoor events outside of just the games, including concerts, and larger events like the NCAA tournament.
Infastructure:
Parking is already hard enough in Oakland during a bball game, and if you park in a garage, it already can take over an hour to get out of it. Now triple the crowd, or quadruple it.... Also, the idea if shuttling people has been floated, up ton10 or 20k if the crowd. How do you accomplish that? You would literally have to have about 500 buses at the ready if you assume a bus seats 100 people. That once again is not reasonable.
Location:
Quite simply, there is not currently a good spot. Up behind the Pete would be a logistical nightmare. Honestly, I would stop buying tickets if it was up there. Anywhere else you have to starting tearing down buildings, and buying land that would cost a ton of money.
Cost:
Speaking of money, where does it come from? Pitt's first priority is education, so it shouldn't be fully funded by the university. Tax payers aren't going to agree to it. We aren't raising the money either. Pitt fans are notoriously cheap, so we ain't getting 300 million dollars.
Basically, this while idea really needs to be taken out back and shot.