[tmax63]

As someone said earlier, changes in coaches, scheme, culture and personnel on defense. It was needed last year. Berry, Houston and Ford all need to go. EB has played 3 games in the last 2 years. JH has played in about 2/3 of the games since becoming a 100 million dollar man. Ford was considered by most to be a bust until last (his contract) year. As a team you don't want that kind of "lead from the bench" mentality.
Worried about replacing the sacks. Ford and Houston benefited from Jones beasting in the middle. Whoever returns/replaces them will benefit as well.
SS/box safety was the weakest link last year. Anyone who thinks that stopping a run for 3 yards to create a "2nd and 7 or 3rd and 6" instead of a "2nd and 3 or 3rd and 2" doesn't impact the game in a dramatic way is sorely mistaken. Stopping a TE for an 8 yard completion instead of an 11 yard 1st down can definitely change a game's outcome.
Losing a game when you score 50 points tells me that it wasn't just the coaches, players, or scheme adjustments it was all of them. Stopping after changes to the coaches and scheme is like setting mousetraps in the kitchen but not in the pantry. It might look like you got them for a while but they'll be back.