I don't know about a stadium, though a stadium and arena across from SSW seems like a great idea. But that land should have been earmarked for Pitt from day one. It's a logical expansion location and yet there was never a chance that the city was going to allow it. Imagine a river campus with a few schools, residence halls, etc... with great riverfront parklands connected to Oakland by trams. Would have been great for Hazelwood as well. Instead they are going to use prime real estate for more windowless labs (like most of the other stuff along 2nd). Makes about as much sense as using the space for testing driverless cars.
I love Pitt but hate Pittsburgh for the lack of care they seem to give to our university. Our administration doesn't seem to have much of a bigger picture either. But they could put this kind of stuff anywhere.