St Louis broke their end of the agreement in terms of the top tier clause, that's why we're in this miss. There are other cities who have this same clause (which I didn't actually know).. So if they let St Louis break that part of the lease and then offer up something that doesn't qualify into the top tier, then it's setting a bad precedent for the other cities.
In terms off what makes a stadium "top tier" I'm not really sure how the NFL qualifies it. My guess is size, ability to host the superbowl, and things like that.
So the top tier was what, the top 8?
Dallas, Indy, SF, Houston, Arizona are probably all above it, some easily, they're new or relatively new stadiums that the NFL can put multiple Super Bowls in no problem. Minnesota's plan tops the Riverfront, and whichever LA stadium would also likely top it. Because of the low number of seats and press boxes (requirements for top tier) it probably pushes it behind NY and a few others.