Yes, there is a big difference. And there is a big difference in cost. In fact most cities (if the city is paying) would consider a retractable roof to be prohibitively expensive.
Not only are they incredibly expensive; they are also hardly ever open. Look at Miami, Phoenix, and Houston, for instance. It seems that only when the weather is perfect do the games see sun(moon)light. Too cold? Too hot? Too humid? Keep the roof closed! Those stadia have effectively become domed. Only very seldom have I seen Houston and Arizona with the roofs open. Has anyone ever seen Miami's open? I think I recall once during its first year.
Bottom line: Stop whining about the weather. We get a rare spurt of endless rain and nambies shout for roofs. Tough it out. Better yet, move to Green Bay and go to the winter Packer games (good luck getting tickets). Packer fans put all domed/roofed fans to shame, whatever their supposed-to-be-outdoor sport. They even grow grass, to boot.
