tight end, yet you think he hasn't developed? He's due for a monster year.
If you start counting the players that didn't develop that you think should have, Bronco is the worst coach of all time. The 4 and 5 star players that just flopped is a mile long under Bronco. There are a lot of factors that come into play (talent, self-motivation, injury history, scheme, work ethic, etc.) The coaches only factor in so much, before you have to look at player accountability.
Regardless, there are a ton of players that have improved in the Sitake era. This is a terrible argument.