Considering I was about to literally write the same thing as Joe Barker (who used to be the hockey editor here at SBNSTL) just wrote on St. Louis Game Time, I figured I might as well go on and link to it instead of re-saying everything that he did.
He brings up many good points, the biggest one is this: the roster's set sans David Perron:
Which leads us to David Perron. Months and months have gone by since his concussion and he's still not cleared to work out. Perron is easily a top-9, possible top-6 guy, but he doesn't really fit in on this team. Sure, D'Ags could slide down to the fourth line and such, but it just doesn't really make sense. To me, bringing in Langenbrunner and Arnott means the Blues aren't expecting Perron back. They're trying to not get caught shorthanded.
If Perron does come back, the Blues just have more depth.
Perron still hasn't been cleared for on-ice workouts yet. It's going to take some working out and focus to get him back in hockey shape - he hasn't played in around nine months. Joe makes the guess that Chris Nichol will be your fourth line left wing, with Ryan Reaves taking the Cam Janssen role.
Basically, what this signals is that aside from some depth moves, the Blues are done at forward - and probably in general. The line up looks significantly better than it did, and the team might be starting off improved from last season's. The trick here is for injuries to not decimate the club, but with Jamie Langenbrunner and Jason Arnott's ages, it's hard not to imagine they won't sit out for a game or two here and there. Here's hoping it's not for an extended trip to the IR.