This will be short but feel free to add your thoughts.
Looking at Arsenal from at each position (generally) from last season to where they sit today after the close of the transfer window.
GK: Szczesny has changed his # and I am going to assume has gotten better since last year so that position is trending up
RB: Sagna is still solid and now we have a young back up. even
CB: Having Vermaelen back and signing Mertesacker with a hopefully improved Koscielny and Djourou means that this is a much improved part of the team, biggest upgrade from last season
LB: Clichy gone with Santos coming in and Gibbs perhaps staying fit enough to play. I am going to have to say this is slightly worse, but perhaps even.
DM: Song will hopefully improve with Frimpong getting some minutes. Depending on our formation there will be 1 or 2 DMids, with Wilshere most likely moving more forward this season. I am going to say this is still about the same for us in quality.
Wide Mids: Last season was Nasri, Walcott, and Arshavin with some Bendtner. Now we have Gervinho, Walcott, Arshavin, AOC, Ryo, Park... Losing Nasri is tough as he had a few good months and always kept other teams on their toes. So far Gervinho has created well when on the field, making good runs with the ball. Walcott is continueing to be dangerous with his speed at times. It will be interesting what contributions we will get from the younger players and Park if he plays out there. I feel this is our deepest and probably best position(s). I feel we are better off here than last season.
CM: Fabregas' role, so obviously a step down here. To fill this we have Arteta, Benayoun, Rosicky, Ramsey, Diaby and Wilshere. It seems this season we are playing with 2 forward mids instead of one, so finding the right combinations is key. The first 3 players are older and hopefully will play well over the next couple seasons. Jack and Aaron's development will determine if this is a strong position for of or one of need. For this season we are worse than last year, but do have more options now and hopefully the players for the future.
ST: RVP will hopefully stay fit and continue his last season form. Behind him we have Chamakh and Park, instead of Bendtner. RVP is very good, but this is a very week position, hasn't changed much from last season, but I am not very confident with our forwards, especially if its not RVP in the game.
In summary I feel this is a much better defensive team than it was last season, although the midfield creativity will be lacking. Because of the lack of depth up front, this team will rely on its wide players to create and score. We should be better off defending and scoring on set pieces, especially with Vermaelen and Per in the line up. A lot will be riding on how well the new additions are able to fit in and take some pressure off of the young players.
I am excited to watch this squad play and really think we could be a great defensive team (what 8 goals?). A breakout season fro any of the following: Wilshere, Walcott, Arshavin, Gervinho, Park, Ramsey, could really get this team moving in the right direction.