Your points are well laid out:
Bronco and his staff (and wife) should see what the media and the fans say as a chance to learn and grow, rather than shy away from such opportunity. It is EXTREMELY useful to inspect what fans are clamoring for. As they say in business, "The customer is always right." If the fans want something, Bronco ought to be willing to listen and give the fans what they want, considering it is a reasonable demand. Bronco is not a bad man or even a bad coach. He does many amazing charitable things and is a fun guy. However, when it comes to the football aspect of his employment, his refusal to accept criticism or heed the desires of his fan base will eventually end in his departure.
If they are the experts, then they should be able to sift through the things fans say or do or demand and recognize what is reasonable and what is based on a sound understanding of the game and the coaching process and if it works to their advantage, implement it.
But there is a media ban in the Mendenhall household and I am willing to wager that most angry letter Bronco receives are tossed quickly in the garbage as insane drivel.