What about this proposal precludes Zygi from building his ramp too? Seems likely to me that Zygi's going to do whatever he wants and only cares about this proposal to the extent that it will compete with his. And it's hard to argue that Zygi doesn't have the ideal location for stadium parking, no matter how many spaces are built a couple blocks away.
My understanding is that the stadium commission is obligated by legislation to build the parking ramps for Zygi -- he's not building them himself. So, to the extent that parking at this location meets the intent of the legislation, I'm not sure there's much he could do about it.
But let's say that he decides that these ramp locations aren't up to snuff -- what's in it for him? A couple things come to mind. First, he could agree to go "halfsies" on these ramps with Ryan, saving a chunk of money that the stadium commission could then spend on other stuff that he wants (like a retractable roof or nacho cheese fountains in the Ultra-NFL Gameday Experience Logia). In addition, since Zygi already owns the land that the ramps were originally going to be built on, he could potentially keep those lots for himself to develop something more lucrative than parking ramps.
Let's remember -- the surface lots around the Metrodome were profitable because they were getting used by the Twins, Gophers, and Vikings, 100 days a year for high-buck event parking. Now, you're going to try to finance expensive structured parking based on only 10 events a year. I don't think it works; that is, I think that Zygi knows the stadium ramps wouldn't be profitable if they had to pay their own capital costs.