It's easy to point at the Seguin trade and go SEE! THERE! But they dealt Seguin for a universally panned return and won the President's Trophy last year. The problems are beyond one roster move, and some of them are as followed:
1. Chiarelli never replaced Iginla. Krejci and Lucic put up good results and good numbers when they had Nathan Horton or Jarome Iginla on their right. What's the common factor? Size and skill. Both Horton and Iginla used their physicality to get in front of the net and score, and complemented Lucic's physical game on the other side. Letting Iginla walk, instead of acquiring another forward, they tried to replace him internally and wound up with Seth Griffith playing there most of the year. I like Griffith, but he's not cutting it there, the downgrade from Horton->Iginla->Griffith on the first line playing first line minutes is going to have the net effect of costing the Bruins a lot of goals scored. Note that they're losing a lot of 1-goal games as well.
2. An aging secondary core combined with a coach who defers to veterans over rookies in almost all situations. Greg Campbell is cooked, Chris Kelly is no more than a good 4th liner and penalty killer, Simon Gagne should not be an NHLer anymore. Julien is giving all these guys way more minutes than they should be getting while youngsters like Spooner, Khokhlachev, and Pastrnak don't get a shot because they're not defensive wizards who fit the "system" yet.
3. Inverse from the previous point, between injuries and trades, the defense has been composed of mostly inexperienced prospects all year. When Chara and McQuaid got hurt, the defense corps for a full month was Seidenberg (who has looked rusty since coming back from his ACL) and 5 guys under the age of 25. You have the likes of Bartkowski, Trotman, and Morrow playing more than they need to. And when the D is healthy, they can put out a third pair with a defensive D-man like Kevan Miller to hold the fort and allow Torey Krug to do his thing offensively, but when your personnel is compromised, you can't shelter Krug and A. his defensive flaws have been exposed more often and B. needing to cover himself defensively, he's not as free to create offense from the blue line.
4. Injuries. Krejci being out most of the year has hampered the team. Carl Soderberg is the best third line center in the NHL. When Krejci is healthy and we can roll out Eriksson-Soderberg-Kelly/Fraser against a third or fourth line and a third defensive pairing, they create offense. When Krejci's out and Eriksson-Soderberg-Fraser have to go up against opposing top lines and top defense pairs, they get shut down.
There are many more reasons but I think these three more than any show the way that things have gone so far. I feel like the team is at a point where if they can make a trade for a winger to stick with Lucic and Krejci, they can recover and be a threat in the eastern conference again, but if they do nothing and let things slide, they're going nowhere.
