This is just silly.
No one should be comparing apples to oranges with these new stadiums. Sunlife stadium is perfectly fine.
Even if the stadium is renovated or a new one is built, in five years we'll be back here talking about how it doesn't compare with the brand new stadiums. That's how technology goes. Give it five years, and the big screen in the Cowboys stadium will be replaced for an even bigger, more high definitioner holographicer screen. The city of Dallas will be the first city to owe a trillion American dollars all by itself. This is the nature of technology: you cannot future proof your fancy gizmos.
Want a new stadium, Miami Dolphins? Win. Win it all. Go primetime and even the local politicians will see that you need a new home stadium to play in.
For now, focus resources on keeping your fans in attendance comfortable at the game. Shield them from the sun. Keep them feeling cool. Renovate what matters to us, your loyal customers. Miami has always been one of the worst climates to watch an outdoor sport in. Fix that.