Given the tone of your post, you seem to be accepting of the direction the team is taking. However, you spend way more than enough time here to claim that you need this to be explained to you. You are involved in most discussions and the same points are being debated with you and others on a daily basis. I doubt very much that you need any further explanations.
Bergevin is out of his depth, on several moves he has made. Most of us have been saying that the team is poorly constructed since this summer. The team is cratering since the start of the season -- it's seriously exposed. Craig Button summarized the situation best:
There are several deficiencies that should not have been present in Year 6 of Bergevin's tenure. The team's poor construction is on him. As is the lack of quality organizational depth, the absence of a true no. 1C, no first pairing LHD, no elite puck moving D. He didn't address the pressing need for primary and secondary scoring, which have been dogging the team especially in the playoffs. And this year, the way they're playing, they won't even need to worry about the playoffs, their chances of making them are very slim and getting slimmer. Poor asset mix continues to be a factor. I don't know how much more evidence is needed, he's had 5 years to attend to these issues. Seems obvious to me and most here that it's time for Bergevin to hand over the reigns to someone else. I have no idea how this is even debatable.
