I present a thought for improvement that can take place not only now, but also over the offseason.
The OL is an obvious problem, and has been the weak link on the offense. Even during the win streak, it was only productive on an average level, although that allowed skill players to be more effective. A more effective OL translates to more production from skill players.
Take a OT that was well-rated, as high as a second-rounder, from a small school, one who was dominant at a lower level of competition. A 6'6", 311 lb OT that has very good tangibles: size, strength, and quickness. Tony Washington, a player whose skills results were very similar to Bruce Campbell's: 225lb bench - TW 33, BC 34; vertical - TW 29.5, BC 32; broad jump - TW 9'6", BC 8'5"; 3 cone drill - TW 7.52 sec, 7.58; 20 yard shuttle - TW 4.6 sec, BC 4.69; 40 yard dash - TW 5.09, BC 4.85.
Does he have off-field issues? Yes, from his youth, but he hasn't been in trouble for years, and has shown a desire to compete, and a chip on his shoulder to prove that he can play. Can much more be asked of a player, especially one with such physical gifts?
Sign him for peanuts, put him on the practice squad or even on the roster to make sure nobody else signs him. I would wager that by next season, he will be ready to play. At worst he would be only as good as Walker. It seems that B Campbell is going to be looked at more as a OG, which may or may not be where he ends up. Best case scenario: LT Veldheer, LG Loper, C Satele, RG Gallery, RT B Campbell, with Barnes, Henderson, and Washington as backup OT/G's. (I moved Gallery to RG to help Campbell transition) Draft a young, more capable C, and you have a OL that averages 26 years old or less, with only 1 player (Gallery) that is even 30; if the game is won and lost in the trenches, then you have set your trench for some time...