- Karlsson coming off another major injury, not at the elite level they need him to be (and really struggling defensively)
- MacArthur missing a 3rd season in a row : career likely over (a top-6 forward never replaced)
- Ryan keeps getting injured, hard to produce consistently (injury-prone at this point)
- Anderson is 36 y/o (declining), rolled on a emotional high last season. Condon isn't good enough to help carry the load.
Maybe "playoff hangover" is a factor (like the Pens) but outside of those 4 players, the rest should be okay (even if some were coming off injuries like Brassard, Ceci, etc). Hoffman, Stone and Brassard are producing fine but the team is broken. Boucher has been able to have short term success but again, he is not able to maintain it. He might have tired some players with too much rigidity. Losing Methot (damn expansion) and now Turris (good swap on paper but probably horrible for the team cohesion) was too much to lose suddenly in terms of roles and leadership.
That team proved that they could win last year + playoffs (98 pts despite injuries and adversity and we know what happened in the playoffs). They also had a pretty good start where they were 6th in Pts% and 3rd in GF after 16 games (so we're talking about 120+ games). Then they came back from Sweden with Matt Duchene and the season went downhill.
This is obviously not a "personnel" or talent problem but more a team problem : they are not working well together. A coaching change would have probably sparked them back but at some point, can't change the coach every 1.5 seasons, that's a lot of dead money spent.