For some reason I just found this thread and wanted to share my experience.
I grew up in FL; I know heat and humidity. I went to University of Miami for undergrad, I have been at Hardrock many, many times.
I was at the game last week, seated on Visitor side, 30 yard line, in the sun the entire game.
It was absolutely unbearable being in the sun. Heat is one thing, and everyone in the stadium feels heat, but to be in the sun is an entirely different experience. I would estimate the "feel" temperature of being in the sun was probably 20 degrees or more higher compared to the shaded portions of the stadium. There was zero cloud cover the entire game.
I know people want to downplay the effects of the stadium design, but the reality is that it Definitely makes a huge difference to have one team in the sun and the other in the shade. Also, this is the tropics... the sun is stronger than in NY or higher latitudes due to the angle of being closer to the equator. Buffalo brought out these dinky little PVC shades, but those only covered a small area of the bench. Players standing on the sidelines received no benefit. In years prior there was cloud cover which provided relief. The NFL absolutely needs to address this issue. If it makes no difference why doesn't Miami have their bench in sun? It's because it does make a difference.