I think our one-dimensional style, lack of real talent and inexperience all played a hand in this. Once the book was out on how to discombobulate our D, there were never adjustments made to counter that book because the focus was on execution. But they're not going to get Nashville-style execution with the lack of talent on one side, and the inexperience on the other.
Goal-tending suffered, then, because a lot of the shots against were either high-quality, or took advantage of the chaotic D. On the last point, there were way too many "flukey" goals for them to be random. I guarantee part of the book was to lob the puck from below the dots 90 degrees at a Sabres D man in front.
Both goalies were sufficiently rattled starting in late December and never recovered. While the latter half of the season has shown us our goalies do not have the mental fortitude or technical skill to be number ones, I think nearly any good goalie would have looked bad in front of our D.
Injuries, lowering confidence, inability to maintain the appropriate pace throughout the season, and general positional and in-game strategic confusion was added to an already teetering D core, which features a lack of appreciation for puck possession, an inability to control zone exits, and at least half who can't stand the thought of laying a hit or receiving one to make a play.