But wasn't the Ballpark in Arlington built in the parking lot of the Rangers' previous stadium? That land was already owned by Rangers.
Nope, they took private lands as well. There's a good summary here:
http://emdo.blogspot.com/2005/05/demolishing-sports-welfare-reason.html
I believe this is why we haven't seen W come out against the Kelo decision. His opponents would hammer him with the Rangers' sweetheart deal.