The problem is, the area is currently a wasteland, a total wasteland. When the Brewers aren’t in town, no one is there. There isn’t an economic area to bolster, supplement, and feed off of. How do you find tenants/builders when the area will be dead over half the year? Not to mention, compete with tailgating (good food and beer that is cheap). The Deer District, STL Cardinals district, and even Lambeau Field don’t really have to compete with people bringing their own food/beer. The Brewers have done little pop-up tailgate/attraction areas in the parking lot before and they are always a flop.
On another note, I think winterizing AmFam is probably largely due to the system needing replacement anyway and the cost to bolster it is probably not that much in the grand scheme. While most larger stadium tours are in the summer, I think there are still plenty of events that take place in the winter they would be looking to attract.
Certainly, it would give Milwaukee a very unique venue that has no real comparable nearby as Chicago and Minneapolis both have outdoor baseball stadiums. Is there an interest in a venue size between that of a basketball arena and a football stadium? I don’t think them hosting Badgers basketball was a coincidence, I think they would bid for an Elite 8. They have had it at Lucas Oil Stadium, so clearly there is an appetite for a bigger venue than a basketball arena can hold.