He didn't have a ton of talent to work with, but the one thing which I think is kind of damning is that the receivers made no progress throughout the season.

A mark of good coaching is that even when a season starts out badly, you can at least see that players have taken steps forward at the end of the year. I didn't see that with our receivers this year. They were still not running good routes and were struggling to create separation, which is something that can be taught even if a player is lacking in natural athleticism.