I can see your point for sure, another airport area convention center will kill the IX center probably. I will also say Indy is a good comparison, but a stadium is so much more than the IX center. Final 4's, super bowls, Bowl games, on top of major convenntions. It wont be as popular as something in Phoenix, nor is the area nearly as populated. But, Haslam is counting on the area being lucrative and the whole area will get a face lift and restarants and bars. It will be much better than the IX Center alone.
Plus the IX center is an 80 year old building, vs a brand new building and even neigborhood.