With regard to BB not using AD properly, a case can be made....
According to Profootballfocus.com....
AD played 601 snaps last year and rushed the passer 124 times. He had a total of 3 sacks, 3 Qb hits and 5 pressures which ave. out to a "impact" plays on the QB every 11 snaps.
By comparison, Dumervile played 880 snaps, rushed the passer 419 times and averaged an "impact" play every 7.6 snaps.
In theory, if AD rushed the passer the same amount as ED, AD would have 295 more pass-rush opportunities and as a result 26.3 more "impact" plays. Assuming that 27% of ADs "impact" plays are sacks, with the same number of pass rushes ad ED, AD would be on a pace to record 10 sacks, 10 QB hits and 15 or so pressures.
This is all Bill James nerd-hypothesis but at least mathematically you can make the case that BB did not use AD properly. If he played him more, he would have gotten more production. However the guy is in his early 30s. Not sure if BB felt he had the stamina to hold up. Also, how many of those additional opportunities would have been taken away from TBC who had a very good year?
BB has always said that the best time for trades is either the draft or right before the season during final cut-downs. If BB and AD can't get on the same page, I suspect that he'll be gone before the draft either via trade or released outright.