While BigA and David are right in the points they were making, there has been a movement in the past 20-25 years to build more sports stadiums in the hearts of cities, though they are usually smaller stadiums for baseball and basketball rather than football (here in Sacramento, the NBA Kings---our only pro franchise---have moved from suburban Sleep Train Arena to downtown's Golden 1 Center).
Since you are obviously a better researcher than me (and 99.99% of the population knows more about pro sports than me) I wonder if there is any data on how many stadiums (stadiae?) have been built on land acquired by exercising eminent domain laws.
This thread has involved the tarnish on the Dodger Stadium caused by displacing a poor but vibrant Hispanic neighborhood through that legal procedure. So now I am wondering if any other major baseball, football, basketball or other large arena or stadium based sports has used that method to get the land for a new facility.