Madden was the best making things interesting during blowouts. My favorite Madden moment was seeing a Thanksgiving game where the Cowboys were absolutely destroying their opponents (can't remember who), and Madden decides to use the tele-strator to draw circles around water buckets on the sideline, and proceeds to label them, by size, "you need a big ol' daddy water bucket, and then over here, to make sure there's not just one line of guys waiting, you have a mommy water bucket, and then, over here, there's a guy who's so special he just brings his own baby water bucket."
Plus, on more than one occasion, I remember him advising GMs to make sure that somewhere on their roster, they "need at least guy named Tank, Spike, or Bubba". It was important to team chemistry to have that guy, you see. And most of the teams he coached had that kind of guy in Oakland.
My whole thing is this... John Madden coached over 100 games, and of any coach to achieve that, he still, to this day, has the highest winning percentage. He helped build the mythos of the Raiders and arguably did as much for it as anyone outside of Al Davis. Then he goes into commentating and spends 30 years from '79 to '09 covering a game a week, and during that stretch, FOURTEEN Super Bowls. If you watched football at all during that stretch, Madden was a part of your football core memories. And if he wasn't, and you were a kid... the Madden video game. And, of course, he's the reason comedian/impressionist Frank Caliendo got launched into a full career.
John Madden is a part of the football zeitgeist and made the game reach more people than possibly any player, coach, commissioner, or commentator in its history.