Agreed.
I think teams should be allowed to bring whatever equipment they need for player comfort and safety on the sideline. For for Buffalo, this would mean we could bring sun shades and water misters when we play in Miami in September. For Miami, they can bring seat heaters and whatever they need to stay warm on the sideline in cold weather games.
Beyond that, everything should be equal on the actual playing field and the weather or elements will affect both team equally and indiscriminately. I really don't know why the NFL hasn't evolved their sideline equipment policy because there are certainly VERY LEGITIMTE player safety concerns. The Bills playing in 112 degree heat in Miami isn't safe- just as it wouldn't be safe to stand around in -25 windchill for the Miami and Chiefs players this weekend.